1Thess 3:2

“Whenever anything happens to the helmsman, either the officer in command at the bows or the seaman of highest rank takes his place, not because he becomes a self-appointed helmsman but because he looks out for the safety of the ship. So again in war, when the commander falls, the chief tribune assumes the command, not in the attempt to lay violent hands on the place of power but because he cares for his men. So too the thrice blessed Timothy when sent by the divine Paul took his place. It is, therefore, appropriate to you as a man of faith to accept the responsibilities of helmsman, of captain, of shepherd, gladly to run all risk for the sake of the sheep of Christ and not to leave his creatures abandoned and alone.”

“Such was the care of the holy apostle Paul for his disciples, that when he himself was detained by some difficult circumstances, he would send others to visit his disciples. This is what he did then as well, sending Timothy. And he speaks of him with such praise, not so much exalting him as honoring them by the fact that one so indispensable at such a time he drew away for their sake from the work of ministry as a "fellow worker in the Gospel."”

“And we sent Timothy, who was the one most in accord with the Apostle: "I have no one like him, who will be genuinely anxious for your welfare" (Phil. 2:20). "I sent to you Timothy, my beloved and faithful child in the Lord" (1 Cor. 4:17). Our brother, sustained by charity. "A brother helped by a brother is like a strong city" (Prov. 18:19), and God's servant, for he is an important person in the Church: "Are they servants of Christ? I am a better one" (2 Cor. 11:23). And so Paul sends Timothy to strengthen the Thessalonians and to report to Paul about them. When Paul says to establish you, he shows that Timothy is sent to strengthen them. So Paul first states this, and second the reason for the strengthening is stated (3:3). Paul says, to establish and to exhort you, for the soul of a man is strengthened through encouragement: "Your words have upheld him who was stumbling" (Job 4:4). When you have turned again, strengthen your brethren (Lk. 22:32).”