Albert Barnes on John 1:19

This is the record. The word record here means testimony, in whatever way given. The word record now commonly refers to written evidence. This is not its meaning here. John's testimony was given without writing.

When the Jews sent. John's fame was great. See Mt 3:5. It spread from the region of Galilee to Jerusalem, and the nation seemed to suppose, from the character of his preaching, that he was the Messiah, Lk 3:15. The great council of the nation, or the Sanhedrim, had, among other things, the charge of religion. They felt it to be their duty, therefore, to inquire into the character and claims of John, and to learn whether he was the Messiah. It is not improbable that they wished that he might be the long-expected Christ, and were prepared to regard him as such.

When the Jews sent priests and Levites. Lk 10:31,32. These were probably members of the Sanhedrim.

(a) "the record of John" Lk 3:15