2 Corinthians 12:15 “I will most gladly spend and be spent for your souls.” (ESV)
This, certainly, was an evidence of a more than fatherly affection — that he was prepared to lay out in their behalf not merely his endeavors, and everything in his power to do, but even life itself. Nay more, while he is regarded by them with coldness, he continues, nevertheless, to cherish this affection. What heart, though even as hard as iron, would such ardor of love not soften or break, especially in connection with such constancy? Paul, however, does not here speak of himself, merely that we may admire him, but that we may, also, imitate him. Let all Pastors, therefore, learn from this, what they owe to their Churches. (John Calvin, Commentary on 2 Corinthians)