John the Apostle
3 John 1:6BSB·traditional attribution

They have testified to the church about your love. You will do well to send them on their way in a manner worthy of God.

Matthew Henry Presbyterian @wholebiblehenry

I. John receives a good report of Gaius's faith and charity from the brethren. Gaius’s love for the brethren and hospitality to strangers proves his sincerity in the faith. II. Gaius is commended for his hospitality, a virtue extended to strangers and those of different churches. III. John expresses great joy in hearing of Gaius's walk in truth.

Commenting on 3 John 1:3-8

John Gill Reformed Baptist @doctorgill

Which have borne witness of thy charity before the church,.... At Ephesus, where John was; these brethren and strangers coming thither, and being greatly affected with Gaius's kindness and liberality to them, could not forbear speaking of it to his praise, in the presence of the members of the church, as well as acquainted the Apostle John with it; the Syriac version reads, "before the...

Albert Barnes Presbyterian @notesbybarnes

Verse 6. Which have borne witness of thy charity before the church. It would seem that they had returned to John, and borne honourab1e testimony to the love manifested to them by Gaius. Before what church they had borne this testimony is unknown. Perhaps it was the church in Ephesus. Whom if thou bring forward on their journey, ουςπροπεμψας.