Theophylact of Ohrid

For this reason, when the Lord healed, those who were healed proclaim Him, despite the fact that He forbade them this and commanded them to say nothing. From this let us also learn, when we do good to others, not to accept praise from them, but when we receive good deeds, to glorify our benefactors and spread word of them, even if they do not wish it.

Commentary on Mark ↗

Augustine of Hippo

If however He, as one Who knew the present and the future wills of men, knew that they would proclaim Him the more in proportion as He forbade them, why did He give them this command? If it were not that He wished to prove to men who are idle, how much more joyfully, with how much greater obedience, they whom He commands to proclaim Him should preach, when they who were forbidden could not hold their peace.

Catena Aurea by Aquinas ↗

Bede

And he commanded them not to tell anyone. But the more he commanded them, the more they proclaimed it, and they were exceedingly astonished, saying: He has done all things well, he makes the deaf hear, and the mute speak. If he knew they would proclaim it even more as he had the present and future wills of humans known, why then did he command this except to show the lazy how much more fervently and eagerly they ought to preach, whom he commands to preach when those who were forbidden could not keep silent?

On the Gospel of Mark ↗