“Jesus straitly charged them, saying, See that no man know it.”—Matt. 9:30.
“Jesus said unto him, Go home to thy friends, and tell them what great things the Lord hath done for thee, and hath had compassion on thee.”—Mark 5:19.
The foregoing remarks may be of some use here. Our Saviour did not wish his miracles to be utterly unknown; for then God would not have been glorified, nor the end of establishing the truth of his Messiahship answered; but neither did he wish to make an ostentatious display of them. First, Because he had no desire of vain-glory about him. Secondly, He did not wish to give any unnecessary provocation to his enemies, which might have hindered him in the execution of his work. Thirdly, Where there was no danger from enemies, yet such was the eagerness of the people to see his miracles, that they flocked together from all parts of the country, thronging and hindering him in preaching the gospel. To the two former of these causes the injunction of secrecy seems to be attributed in Matt. 12:13–20; and to the last in Mark 1:4, which is the case in question, as related by Mark. We are there informed that, owing to the leper having “blazed abroad the matter, Jesus could no more openly enter into the city; but was without in desert places,” which was a serious injury to that work which his miracles were intended to subserve.
But in the country of the Gadarenes the case was different. He was there in no danger of being hindered from his great work by the thronging of the people; on the contrary, they were afraid, and “prayed him to depart out of their coasts;” and he did depart. In such circumstances let not the story of the destruction of the swine be the only one in circulation; let the deliverance of the poor demoniac also be told; and let him be the person who should tell it. Let him leave these people who wanted to get rid of the Saviour, and go home to his friends, and tell how great things the Lord had done for him, and had had compassion upon him. Luke tells us that he published it throughout the whole city, chap. 8:39
Fuller, A. G. (1988). The Complete Works of Andrew Fuller: Memoirs, Sermons, Etc. (J. Belcher, Ed.) (Vol. 1, pp. 667–684). Harrisonburg, VA: Sprinkle Publications.