John 21:7 reads
λέγει οὖν ὁ μαθητὴς ἐκεῖνος ὃν ἠγάπα ὁ Ἰησοῦς τῷ Πέτρῳ· Ὁ κύριός ἐστιν. Σίμων οὖν Πέτρος, ἀκούσας ὅτι ὁ κύριός ἐστιν, τὸν ἐπενδύτην διεζώσατο, ἦν γὰρ γυμνός, καὶ ἔβαλεν ἑαυτὸν εἰς τὴν θάλασσαν·
Therefore that disciple whom Jesus loved saith unto Peter, It is the Lord. Now when Simon Peter heard that it was the Lord, he girt his fisher's coat unto him, (for he was naked,) and did cast himself into the sea.
Donning a coat is an odd way to prepare for a swim (even (especially!) in hasty preparation). Working in the nude also seems to defy Jewish sensibilities.
BDAG is clear that γυμνός does not necessarily mean completely naked (and this is variously reflected in more recent translations), excerpted from the second and third entries1 (the first is "naked")
2 pert. to being inadequately clothed, poorly dressed.... 3 pert. to being lightly clad, without an outer garment, without which a decent person did not appear in public....[John 21:7 is mentioned as a likely example here.]
It makes sense to me that he might be working in his undergarments and feel inadequately clad to meet the Lord. However, swimming in a coat just seems like a bad idea.
The NET bible has an interesting take on it, quoting the footnote2 on v. 7, italics original:
The Greek verb used (διαζώννυμι,diazwnnumi) does not necessarily mean putting clothing on, but rather tying the clothing around oneself (the same verb is used in 13:4-5 of Jesus tying the towel around himself). The statement that Peter was “naked” could just as well mean that he was naked underneath the outer garment, and thus could not take it off before jumping into the water. But he did pause to tuck it up and tie it with the girdle before jumping in, to allow himself more freedom of movement. Thus the clause that states Peter was naked is explanatory (note the use of for), explaining why Peter girded up his outer garment rather than taking it off – he had nothing on underneath it and so could not remove it.
However, I don't know if there's any precedent for γυμνός to mean "missing the undergarments." It's also not clear to me why he would be working with an outer garment only. (Normally, wouldn't one expect to strip the outer and leave the inner, which are presumably less cumbersome to work in?)
Are there insights from historical background, further explanation of the words here, or other information in the text that might help us understand:
- How was he likely dressed (or undressed)?
- What did he do before diving onto the water?
1. Bauer, Danker. A Greek-English Lexicon of the New Testament and Other Early Christian Literature (3rd ed.)
2. Footnote 19 by their numbering. It mentions that the idea is R.E. Brown's, but I don't have the complete citation.