Mark 1:45

(non occ.) For the leper every where proclaimed his wonderful cure, so that all ran to see and to believe on the Healer; thus the Lord could not preach the Gospel, but walked in desert places; wherefore there follows, And they came together to him from all places.

(ubi sup. v. Greg. Moral. 19:22) Now it may well be asked, why our Lord ordered His action to be concealed, and yet it could not be kept hid for an hour? But it is to be observed, that the reason why, in doing a miracle, He ordered it to be kept secret, and yet for all that it was noised abroad, was, that His elect, following the example of His teaching, should wish indeed that in the great things which they do, they should remain concealed, but should nevertheless unwillingly be brought to light for the good of others. Not then that He wished any thing to be done, which He was not able to bring about, but, by the authority of His teaching, He gave an example of what His members ought to wish for, and of what should happen to them even against their will. Further, this perfect cure of one man brought large multitudes to the Lord; wherefore it is added, So that he could not any more openly enter into the city, but could only be without in desert places.

(in Marc. i. 10) Even after working a miracle in that city, the Lord retires into the desert, to show that He loves best a quiet life, and one far removed from the cares of the world, and that it is on account of this desire, He applied Himself to the healing of the body.

But the leper, although the Lord forbade him, disclosed the benefit, wherefore it goes on: But he having gone out, began to publish and to blaze abroad the tale; for the person benefited ought to be grateful, and to return thanks, even though his benefactor requires it not.

But in that Jesus could not openly enter into the city, it is meant to be conveyed, that Jesus is not manifested to those, who are enslaved to the love of praise in the broad highway, and to their own wills, but to those who with Peter go into the desert, which the Lord chose for prayer, and for refreshing His people; that is, those who quit the pleasures of the world, and all that they possess, that they may say, The Lord is my portion. But the glory of the Lord is manifested to those, who meet together on all sides, that is, through smooth ways and steep, whom nothing can separate from the love of Christ. (Rom. 8:35)