Or know ye not that so many of us as were baptized into Christ Jesus were baptized into his death! ἢ, if taken in the sense of "or," at the beginning of Romans 6:3, will be understood if we put what is meant thus: Do you not know that we have all died to sin?
Or are you really ignorant of what your very baptism meant? But cf. Romans 7:1, where the same expression occurs, and where ἢ appears only to imply a question. The expression βαππτίζεσθαι εἰς occurs also in 1 Corinthians 10:2 and Galatians 3:27; in the first of these texts with reference to the Israelites and Moses.
It denotes the entering by baptism into close union with a person, coming to belong to him, so as to be in a sense identified with him. In Galatians 3:27 being baptized into Christ is understood as implying putting him on ( ἐνεδύσασθε) The phrases, βαπτιξεῖν ἐπὶ τῷ ὀνόματι, or ἐν τῷ ὀνόματι, or εἰς τὸ ὄνομα, were understood to imply the same idea, though not so plainly expressing it.
Thus St. Paul rejoiced that he had not himself baptized many at Corinth, lest it might have been said that he had baptized them into his own name ( εἰς τὸ ἐμὸν ὄνομα), i.e. into such connection with himself as baptism implied with Christ alone.
Doubtless in the instruction which preceded baptism this significance of the sacrament would be explained. And if "into Christ," then "into his death." "In Christum, inquam, totum, adeoque in mortem ejus baptizatur" (Bengel).
The whole experience of Christ was understood to have its counterpart in those who were baptized into him; in them was understood a death to sin, corresponding to his actual death. This, too, would form part of the instruction of catechumens.
St. Paul often presses it as what he conceives to be well understood; and in subsequent verses of this chapter he further explains what he means.