The Apostle Paul
Philippians 2:21ESV·traditional attribution

For they all seek their own interests, not those of Jesus Christ.

John Calvin Reformed @genevareformer

21 For all seek their own things. He does not speak of those who had openly abandoned the pursuit of piety, but of those very persons whom he reckoned brethren, nay, even those whom he admitted to familiar intercourse with him. These persons, he nevertheless says, were so warm in the pursuit of their own interests, that they were unbecomingly cold in the work of the Lord.

Matthew Henry Presbyterian @wholebiblehenry

Paul takes particular notice of two good ministers; for though he was himself a great apostle, and laboured more abundantly than they all, yet he took all occasions to speak with respect of those who were far his inferiors. I. He speaks of Timothy, whom he intended to send to the Philippians, that he might have an account of their state.

Commenting on Philippians 2:19-30

John Gill Reformed Baptist @doctorgill

But ye know the proof of him,.... They had had an experiment of him, a trial of his spirit, and a proof of his gifts and ministry, when he was among them with the apostle at his first preaching the Gospel to them, to the conversion of Lydia, and of the jailer, and their households, which laid the foundation of a Gospel church state among them, see Act 16:3.