John Gill Commentary John 1:40

"One of the two that heard John [speak], and followed him, was Andrew, Simon Peter`s brother." — John 1:40 (ASV)

One of the two which heard John [speak]
The above things, concerning Jesus being the Lamb of God:

and followed him ;
that is, Jesus, as the Syriac and Arabic versions read; and the Persic version, Christ: and the Ethiopic version, "the Lord Jesus"; for not John, but Jesus they followed:

was Andrew, Simon Peter's brother :
see (Matthew 4:18) the other, as before observed, might be the writer of this Gospel.