How do we know that God excludes false gods?

In 2 Kings 5, Naaman declares that, after his healing, he recognizes there is no God in all the earth but in Israel. This acknowledgment is a powerful testament to the exclusive truth of Yahweh over all other supposed deities. The gospel is inherently exclusive as it proclaims that there is salvation in no one else, as articulated in Acts 4:12: 'And there is salvation in no one else, for there is no other name under heaven given among men by which we must be saved.' This exclusivity highlights the futility of other religious systems in providing true salvation or knowledge of God.