Popes and Prelates who do not preach Christ are committing mortal sin

 1 Corinth 9:16

16 For if I preach the gospel, it is no glory to me, for a necessity lieth upon me: for woe is unto me if I preach not the gospel. 17 For if I do this thing willingly, I have a reward: but if against my will, a dispensation is committed to me

The Great Commentary Of Cornelius À Lapide Volumes 1 To 8

CHAPTER 9

Ver. 16.—Woe is unto me if I preach not the gospel. It appears from this that strict injunctions were given to the Apostles (S. Matt. 28:19) to preach the Gospel and teach all nations, insomuch that, if they had neglected to do so, they would have sinned mortally. For on those that neglect this their duty he pronounces the woe of the wrath of God and of hell. By the same injunctions all pastors, Bishops, and Archbishops are now bound. Cf. chap. 1:17.

Ver. 17.—For if I do this thing willingly I have a reward. That is, as Chrysostom, Theophylact, Œcumenius, and Anselm say, if I freely preach without charge, I have not merely the reward given to a work that has been enjoined on me, as other Apostles have, but the exceeding reward of abounding glory given to a work not enjoined, but heroically undertaken by a soul that is of its own accord generous towards God.

But if against my will. Compelled by a command of God, or under fear of punishment. Willingly here denotes the doing a thing of one’s own motion, one’s own accord, and free will; unwillingly, the doing it under order, being moved and forced by the will of another.

A dispensation of the gospel is committed unto me. I shall not have that supreme glory I spoke of, but neither shall I sin, because I fulfil my duty, and do what I am ordered. For this commission of preaching the Gospel was intrusted to me. But though I do not sin, yet I act as a slave, or as a steward in matters intrusted to his care, not of his own accord, but merely doing what he ought to do, because compelled to it by his Lord’s command. Cf. S. Luke 17:8. So the Fathers cited understand this passage, and that this is the meaning appears also from the context.

Some explain it differently in this way: If I preach the Gospel willingly I have merit and reward, because of my own free will I fulfil the command of Christ; but if I do it unwillingly, I fail to attain merit and reward, because I act under compulsion. A dispensation of the Gospel is committed unto me, and so by me, though unwilling, Christ’s Gospel is propagated, and others profit, though I do not. This seems to be the simple meaning of the words by themselves. This explanation is favoured by S. Thomas, Lyranus, and the Ambrosian commentary; but the context requires the former sense.