The Gospel is the distinguishing mark between all other false religions

When the apostle speaks "of the testimony of God, the object of saving faith, he tells us, 'it is Christ crucified,' 1 Cor. 1. 23-24. This was the great intent of the prophecies, which spake of the sufferings of Christ, and following glory: 'For to him gave all the prophets witness, that through his name whosoever believeth in him; shall receive remission of sin.' Acts 10. 43. This therefore is that truth of the gospel which is specially witnessed unto, and whereby Christ says, 'his kingdom is advanced in the world.' And this may be further clear unto us if we consider,

1. That this is the distinguishing truth of Christianity, whereby it us differenced from mere natural religion, and from all religions in the world that any way compete with it. This is the great thing, the first thing, that any religion can purpose to sinful men, How they should be pardoned, reconciled to God, and justified in his sight? If the Christian religion differ from others in any thing, it is in this: they purpose other ways of coming into favour with God, and false ways; but Christ has made peace by the blood of his cross, and thereby reconciled all his people, of all nations, unto God in one body; and has come and preacher this peace to them that were afar off, and to them that were nigh, and this is the truth wherein the true God is gloriously manifested and distinguished from every false god." - John Glas, The Works of Mr. John Glas: In Four Volumes, pg. 109