Ye know the proof of him, that, as a son with the father, he hath served with me - The Philippians had full proof of the affectionate attachment of Timothy to Paul, for he had labored with him there, as we learn from Acts 16:1-3; Acts 17:14; and we find from what is said here that Timothy was not a servant to the apostle, but that he had served with him. They both labored together in the word and doctrine; for apostles and Christian bishops, in those times, labored as hard as their deacons. There were no sinecures; every one was a laborer, every laborer had his work, and every workman had his wages.
But ye know the proof of him - You have had evidence among yourselves how faithfully Timothy devoted himself to the promotion of the gospel, and how constantly he served with me. This proves that Timothy was with Paul when he was at Philippi.
As a son with the father - Manifesting the same spirit toward me which a son does toward a father, and evincing the same interest in my work. He did all he could do to aid me, and lighten my labors and sufferings.