Greatly desiring to see thee; - see 2-Timothy 4:9, 2-Timothy 4:21. It was probably on, account of this earnest desire that this Epistle was written. He wished to see him, not only on account of the warm friendship which he had for him, but because he would be useful to him in his present circumstances; see the introduction, Section 3.
Being mindful of thy tears - Alluding probably to the tears which he shed at parting from him. The occasion to which he refers is not mentioned; but nothing is more probable than that Timothy would weep when separated from such a father and friend. It is not wrong thus to weep, for religion is not intended to make us stoics or savages.
That I may be filled with joy - By seeing you again. It is easy to imagine what joy it would give Paul, then a prisoner, and forsaken by nearly all his friends, and about to die, to see a friend whom he loved as he did this young man. Learn hence, that there may be very pure and warm friendship between an old and young man, and that the warmth of true friendship is not diminished by the near prospect of death.

Being mindful of thy tears - Whether the apostle refers to the affecting parting with the Ephesian Church, mentioned Acts 20:37, or to the deep impressions made on Timothy's heart when he instructed him in the doctrine of Christ crucified, or to some interview between themselves, it is not certainly known. The mention of this by the apostle is no small proof of his most affectionate regards for Timothy, whom he appears to have loved as a father loves his only son.

Greatly desiring to see thee,.... In his former epistle he had desired him to stay at Ephesus, there being some work for him to do, which made it necessary he should continue; but now having answered the apostle's purpose, and he standing in need of him at Rome, being without any assistant there, some having left him, and others were left by him in other places, and others were sent by him elsewhere; and it having been some time since he saw Timothy, he longed for a sight of him:
being mindful of thy tears; shed either at the afflictions and sufferings of the apostle, of which Timothy, being his companion, was an eyewitness, and he being of a truly Christian sympathizing spirit, wept with those that wept; or at their parting from each other, as in Acts 20:37
that I may be filled with joy; at the sight of him, and not at the remembrance of his tears; for the last clause is to be read in a parenthesis, and these words stand not connected with that, but with the preceding part of the text. The apostle intimates, that a sight of his dearly beloved son Timothy would fill him with joy amidst all his troubles and afflictions he endured for the Gospel: this is an instance of hearty, sincere, and strong affection.

desiring--Greek, "with yearning as for one much missed."
mindful of thy tears--not only at our parting (Acts 20:37), but also often when under pious feelings.
that I may be filled with joy--to be joined with "desiring to see thee" (Romans 1:11-12; Romans 15:32).

Being mindful of thy tears - Perhaps frequently shed, as well as at the apostle's last parting with him.