“And when the king came in to see the guests, he saw there a man which had not on a wedding garment: And he saith unto him, Friend, how camest thou in hither not having a wedding garment? And he was speechless. Then said the king to the servants, Bind him hand and foot, and take him away, and cast him into outer darkness; there shall be weeping and gnashing of teeth. For many are called, but few are chosen.”- Matthew 22:11-14

Whenever there is a revival and many are brought to Christ, it seems inevitable that at the same time a proportion of unworthy persons should enter the church. However diligent may be the oversight there will be pretenders creeping in unawares who have no true part or lot in the matter, and hence, when the preacher is most earnest for the ingathering of souls to Christ, he needs to couple therewith a holy jealousy, lest those who come forward to make a profession of faith should be moved by carnal motives and should not really have given their hearts to God. We must use the net to draw in the many, but all are not good fishes that are taken therein…It is most needful in times of religious excitement, to remind men that godliness does not consist in profession but must be proved by inward vitality and outward holiness. Everything will have to be tested by a heart-searching God, and if, when He comes to search us, we are found wanting, we shall be expelled even from the marriage feast itself; for there is a way to hell from the very gates of Heaven. In a word, it is well for all to be reminded that the enemies of the great King are not only outside the Church, but they are even in it; while a part refuse to come to the wedding of His Son, others press into the banquet and are still His foes. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/0976.cfm