How did the early Christians baptize?
In the 19th century many scholars denied that immersion was the original mode of baptism. McKay and Rogers wrote influential interpretations of the archaeological evidence, and Dale’s linguistic study became the standard lexical resource for the anti-immersion position.
The Greek word for baptism refers to dipping, plunging, or immersion in both the Septuagint and the New Testament.        
Major studies by Lothar Heiser (1986), Sandford La Sor (1987), Jean‐Charles Picard (1989), Malka Ben Pachat (1989), and Everett Ferguson (2009), all agree the archaeological and textual evidence indicates full immersion was the earliest normal Christian practice.     
The earliest Christian record of baptism outside the New Testament,  proves 1st century Christians normally baptized by immersion.     
The scholarly consensus is that full immersion was the normal practice of the earliest Christians.             
 Among many others, Thorn, ‘Modern Immersion Not Scripture Baptism’ (1831), Kerr, ‘A Treatise on the Mode of Baptism: showing the unfounded nature of the assumption, that immersion is the only proper mode of administering the ordinance and that pouring or sprinkling, is the most scriptural and significant, and by far the preferable mode of its administration’ (1844), Beckwith, ‘Immersion Not Baptism’ (1858), Kerr, ‘The Heavenly Father’s Teaching: a pedo‐Baptist’s reply to immersionists shewing that Baptism is not immersion, and that immersion is not Baptism, for they are direct opposites’ (1874), Bush, ‘Bible Baptism Never Immersion’ (1888).
 McKay, ‘Immersion Proved to be Not a Scriptural Mode of Baptism but a Romish Invention’ (1884), Rogers, ‘Baptism and Christian Archeology’ (1903).
 Dale, ‘Inquiry Into the Usage of Baptizo’ (1824‐1879).
 ‘In the Sept.: 2 Kgs. 5:13, 14 we have loúō (3068), to bathe and baptízomai. See also 28, 40;&version=ESV; Lev. 11:25, 28, 40, where plúnō (4150), to wash clothes by dipping, and loúō (3068), to bathe are used. In 19;&version=ESV; Num. 19:18, 19, báphō, to dip, and plúnō, to wash by dipping are used’, Zodhiates, ‘The Complete Word Study Dictionary: New Testament’ (electronic ed. 2000).
 ‘In Mark 7:4 the verb wash in “except they wash” is baptízomai, to immerse. This indicates that the washing of the hands was done by immersing them in collected water. ‘, ibid.
 ‘The sevenfold dipping of Naaman (2 K. 5:14) perhaps suggests sacramental ideas and illustrates the importance of the Jordan. In the later Jewish period טבל (b. Ber., 2b of the bathing of priests; Joma, 3, 2ff. etc.)’, Kittel, Bromiley, & Friedrich (eds.), ‘Theological dictionary of the New Testament’, volume 1, p. 535 (electronic ed. 1964–c1976).
 ‘Βαπτίζω+ V 0‐1‐1‐0‐2=4 2 Kgs 5,14; Is 21,4; Jdt 12,7; Sir 34,25 M to dip oneself 2 Kgs 5,14; to wash Jdt 12,7′, Lust, Eynikel, & Hauspie (eds.), ‘A Greek‐English Lexicon of the Septuagint’ (rev. electronic ed. 2003).
 ‘baptizō 77x pr. to dip, immerse;’, Mounce, ‘Mounce’s Complete Expository Dictionary of Old & New Testament Words’, pp. 1104‐1105 (2006).
 ‘In Gk. lit. gener. to put or go under water in a variety of senses, also fig., e.g. ‘soak’ Pla., Symp. 176b in wine)’, Arndt, Danker, & Bauer (eds.) ‘A Greek‐English Lexicon of the New Testament and Other Early Christian Literature’, p. 164 (3rd ed. 2000).
 ‘1. In the LXX baptō usually translates the OT Heb. ṭāḇal, dip (13 times; on 3 occasions baptō represents other vbs.). baptizō occurs only 4 times: in Isa. 21:4 it is used metaphorically of destruction, but in 2 Ki. 5:14 it is used in the mid. of Naaman’s sevenfold immersion in the Jordan (the only passages as equivalent for Heb. ṭāḇal).’, Brown, ‘New International Dictionary of New Testament Theology’, volume 1, p. 144 (1986).
 ‘Despite assertions to the contrary, it seems that baptizō, both in Jewish and Christian contexts, normally meant “immerse”, and that even when it became a technical term for baptism, the thought of immersion remains. The use of the term for cleansing vessels (as in Lev. 6:28 Aquila [cf. 6:21]; cf. baptismos in Mk. 7:4) does not prove the contrary, since vessels were normally cleansed by immersing them in water. The metaphorical uses of the term in the NT appear to take this for granted, e.g. the prophecy that the Messiah will baptise in Spirit and fire as a liquid (Matt. 3:11), the “baptism” of the Israelites in the cloud and the sea (1 Cor. 10:2), and in the idea of Jesus’ death as a baptism (Mk. 10:38f. baptisma; Lk. 12:50; cf. Ysebaert, op. cit., 41 ff.).’, ibid., p. 144.
 ‘Lexicographers universally agree that the primary meaning of baptizo G966 is ‘to dip’ or ‘to immerse”, and there is a similar consensus of scholarly opinion that both the baptism of John and of the apostles was by immersion’, Jewett, ‘Baptism’, in Murray (ed.), ‘Zondervan Pictorial Encyclopedia of the Bible’, volume 1, p.466 (rev. ed. 2009).
 ‘The philological evidence is technical and inconclusive. But the archaeological and Mishnaic evidence seems to support the argument for immersion., Sanford La Sor, ‘Discovering What Jewish Miqva’ot Can Tell Us About Christian Baptism’, Biblical Archaeology Review, (13.01), 1987.
 ‘The conclusions of Lothar Heiser on the administration of baptism after examining the literary and pictorial evidence accord with mine: the water customarily reached the hips of the baptizand; after calling on the triune God, the priest bent the baptizand under so as to dip him in water over the head; in the cases of pouring in the Didache and in sickbed baptism the baptized did not stand in the font.’, Ferguson, Baptism in the Early Church: history, theology, and
liturgy in the first five centuries’, p. 860 (2009).
 ‘Either bending his knees, kneeling, or sitting, an adult could have been totally immersed as required in fonts from 1.30m to 60cm deep.’. ibid., p. 852.
 ‘The express statements in the literary sources, supported by other hints, the depictions in art, and the very presence of specially built baptismal fonts, along with their size and shape, indicate that the normal procedure was for the administrator with his head on the baptizand’s head to bend the upper part of the body forward and dip the head under the water.’, ibid, pp. 857‐858.
 ‘The Christian literary sources, backed by secular word usage and Jewish religious immersions, give an overwhelming support for full immersion as the normal action. Exceptions in cases of lack of water and especially of sickbed baptism were made. Submersion was undoubtedly the case for the fourth and fifth centuries in the Greek East, and only slightly less certain for the Latin West.’, ibid., p. 891.
 ‘Later church practice in this regard led artists to the strange fantasy of Jesus standing waist deep in water while John poured water on his head (such pictures do not occur until medieval western times).’, ibid., p. 202.
 ‘It contains details of the church life of the earliest Christians, their preference for baptism by immersion, their fasting on Wednesdays and Fridays, the forms of their eucharistic prayers.’, Manion & Mudge, ‘The Routledge Companion to the Christian Church’, pp. 42–43 (2008).
 ‘In the Didache 7 (a.d. 100–160), the oldest baptismal manual extant, triple immersion is assumed,’ (Silva & Tenney (eds.), ‘The Zondervan Encyclopedia of the Bible, volume 1, pp. 494‐495. (rev. ed. 2009).
 ‘Baptism is by *immersion if possible” (Cross & Livingstone (eds.), ‘The Oxford Dictionary of the Christian Church’, p. 482 (3rd rev. ed. 2005).
 ‘One witnesses the fasting and the solemn rite of baptism, preferably by immersion in flowing water.’, Milavec, “Didache”, p. ix (2003).
 ‘According to the Didache (1st century), baptism should be done by a triple immersion in running water.’, Lacoste, ‘Encyclopedia of Christian Theology: G‐O’, p. 1607 (2005).
 ‘The argument of the section is clear: while adhering strictly to the preference for flowing water and baptism by immersion, necessary concessions are made to local circumstances.’, Draper, “The Didache In Modern Research”, p. 47 (1996).
 ‘As a rule, it involved immersion in running water (see Acts 8:38; Did. 7).’, Fahlbusch & Bromiley (eds.), ‘Encyclopedia of Christianity’., volume 1, p.184 (1990‐2003).
 ‘Baptism is by immersion in the threefold name, but sprinkling three times on the head is allowed in an emergency.’, Vokes, ‘Life and Order In An Early Church:The Didache’, in Haase (ed.), ‘Aufstieg Und Niedergang Der Romischen Welt’, volume 2, p. 221 (1993).
 ‘New Testament scholars generally agree that the early church baptized by immersion.’, Wiersbe, ‘Wiersbe’s Expository Outlines on the New Testament’, pp. 466‐467 (1997).
 ‘Most scholars agree that immersion was practiced in the NT, and it is likely that both of these texts allude to the practice, even though baptism is not the main point of either text.’, Schreiner, ‘Believer’s Baptism: Sign of the New Covenant in Christ’, p. 81 (2007).
 ‘Furthermore, modern NT scholars generally concede, regardless of denominational affiliation, that Christian baptism in NT times was by immersion, as it was and still is in Judaism.’, Helyer, ‘Exploring Jewish Literature of the Second Temple Period’, p. 481 (2002).
 ‘The baptism commanded by Jesus in the making of disciples is an immersion in water. The topic formerly was warmly debated, but in these days there is general scholarly agreement. Several lines of evidence converge in support of the baptismal action as a dipping.’, Ferguson, ‘The Church of Christ: A Biblical Ecclesiology for Today’, p. 201 (1996).
 ‘It seems also that the profession was articulated in responses that the one being baptized made to the questions of the one baptizing during the baptismal rite, which in general was required to take place through total immersion, in total nudity, in running water.’, DiBerardino, ‘We Believe in One Holy Catholic and Apostolic Church’, p. 88 (2009).
 ‘Baptism in the Bible was by immersion, that is, the person went fully under the waters,’, Lang, ‘Everyday Biblical Literacy: the essential guide to biblical allusions in art, literature, and life’, p. 47 (2007).
 ‘The earliest preference was for baptism in running streams or in the sea (Mark 1:9; Acts 8:36; Didache 7). Next in preference was total immersion in a fountain or bath‐sized tank (Tertullian, Baptism 4).’, Flinn, ‘Baptism’, in ‘Encyclopedia of Catholicism’, Encyclopedia of World Religions, p. 52 (2007).
 ‘Baptism was normally by immersion either in the river or in the bath‐house of a large house’, Dowley (ed.), ‘Eerdman’s Handbook to the History of Christianity’, p.10 (1977).
 ‘There is little doubt that early Christian baptism was adult baptism by immersion’, Grimes, ‘Deeply Into the Bone: Re‐Inventing Rites of Passage’, p. 50 (2002).
 ‘Our study has not attempted to demonstrate that affusion rather than immersion was the practice in New Testament times, since it is clear that immersion was the general rule;’, Marshall, ‘The Meaning of the Verb “Baptize”’, in Porter & Cross (eds.), ‘Dimensions of Baptism: Biblical and Theological Studies’, p. 23 (2002).
 ‘We can be fairly sure that early baptism was not normally by sprinkling. Other possible alternatives were pouring (affusion) and immersion. Probably immersion was the norm.’, Guy, ‘Introducing Early Christianity: A
Topical Survey of Its Life, Beliefs, and Practice, pp. 224‐225 (2004).
 ‘In the early days of the Church, total immersion, often in streams or rivers, seems to have been most commonly used (Mark 1:9; Acts 8:3).’, Tischler, ‘All Things in the Bible: A‐L’, p. 59 (2006).
 ‘Saunder and Louw comment, ‘Obviously the phrases “going down” and “coming up” are used to focus on the two processes involved in immersion.’ Clearly the evidence from such accounts favors strongly the notion that baptism was by immersion.’, Ware, ‘Believers’ Baptism View’, in Wright (ed.), ‘Baptism: Three Views’, p. 22 (2009).
 ‘Stander and Louw, Baptism in the Early Church, p. 25, argue similarly for understanding the prevailing practice of the early church to be that of immersion from several other citations of various church fathers and documents, included among them Aristides of Athens, Clement of Alexandria (p. 31), Tertullian (pp. 36‐37), Hippolytus (p. 42), and Basil the Great (who practiced tri‐immersion, p. 82).’, ibid., p. 22.