I thank my God, making mention of thee always in my prayers,

People's New Testament

1:4 I thank my God. Here he begins to speak directly to Philemon, whom he always mentions in his prayers.

Jamieson-Fausset-Brown Bible Commentary

4. always-joined by Alford with, "I thank my God."

Matthew Henry's Concise Commentary

1:1-7 Faith in Christ, and love to him, should unite saints more closely than any outward relation can unite the people of the world. Paul in his private prayers was particular in remembering his friends. We must remember Christian friends much and often, as their cases may need, bearing them in our thoughts, and upon our hearts, before our God. Different sentiments and ways in what is not essential, must not make difference of affection, as to the truth. He inquired concerning his friends, as to the truth, growth, and fruitfulness of their graces, their faith in Christ, and love to him, and to all the saints. The good which Philemon did, was matter of joy and comfort to him and others, who therefore desired that he would continue and abound in good fruits, more and more, to God's honour.