The Apostle Paul
Philippians 1:1ASV·traditional attribution

Paul and Timothy, servants of Christ Jesus, to all the saints in Christ Jesus that are at Philippi, with the bishops and deacons:

Geneva Bible Notes Reformed

Paul and Timotheus, the servants of Jesus Christ, to all the saints in Christ Jesus which are at Philippi, with the bishops and deacons: (1) The Paul's point in writing this epistle, is to strengthen and encourage the Philippians by all means possible, not to faint, but more than that, to go forward.

Matthew Henry Presbyterian

We have here the inscription and benediction. Observe, I. The persons writing the epistle - Paul and Timotheus. Though Paul was alone divinely inspired, he joins Timothy with himself, to express his own humility, and put honour upon Timothy. Those who are aged, and strong, and eminent, should pay respect to, and support the reputation of, those who are younger, and weaker, and of less note.

Commenting on Philippians 1:1-2

John Gill Reformed Baptist

Paul and Timotheus, the servants of Jesus Christ,.... The apostle sets his own name first, as being not only superior to Timothy in age, in office, and in character, but the sole writer of this epistle. The reasons of his joining Timothy with him are, because he was with him when he first preached at Philippi, and so was known unto the Philippians, and respected...