Pencelupan, pembenaman, atau penyelaman, yang juga disebut imersi atau submersi (bahasa Latin: immersio/summersio), dalam konteks keagamaan, adalah tindakan memasukkan tubuh seseorang, baik sebagian maupun seluruhnya, ke dalam air. Cara baptis dengan pembenaman ke dalam air tersebut disebut baptis selam dan/atau baptis celup.[1][2][3][4][5] Baptis selam/celup adalah salah satu cara baptis, selain baptis tuang dan baptis percik.
^McKim, Donald K. (1996), Westminster Dictionary of Theological Terms, Westminster John Knox Press, hlm. 25, ISBN9780664255114, Baptism (Gr. baptizein, 'to dip in water') Initiation into the Christian faith through a worship ceremony in which water is applied by sprinkling (aspersion), pouring (affusion), or immersion while the Trinitarian formula is spoken… Main modes of baptism are immersion (dipping or plunging), pouring (affusion), and sprinkling (aspersion)..
^"In Christianity, baptism—either by plunging in water or by sprinkling with it—represents the first act of incorporation 'into Christ' and into the fellowship of the church." – Fahlbusch & Bromiley (eds.), The Encyclopedia of Christianity, volume 1, (Eerdmans, 1999–2003), p. 183
^"The word baptism is a transliteration of the Greek word baptizo which means to plunge, to dip, or to immerse… In New Testament times baptism was by a single immersion, with triple immersions appearing only later; occasionally, in cases of sickness or lack of water, affusion was practiced" – Myers, A.C., The Eerdmans Bible Dictionary (Eerdmans 1987), p. 123
^"Some form of immersion is envisaged, although affusion is allowed if running or standing water is lacking: 'If you do not have either, pour water three times on the head'." – Martin, R.P., & Davids, P.H. (2000). Dictionary of the later New Testament and its developments (electronic ed.).