Albert Barnes Commentary John 15:27

"and ye also bear witness, because ye have been with me from the beginning." — John 15:27 (ASV)

Ye also shall bear witness. You shall be witnesses to the world to urge upon them the evidences that the Lord Jesus is the Messiah.

Have been with me. They had for more than three years seen his works, and were therefore qualified to bear witness to his character and doctrines.

From the beginning. From his entrance upon the public work of the ministry, Matthew 4:17–22. Compare Acts 1:21-22.