“There is one God, and there is one mediator between God and men, the man Christ Jesus, who gave himself a ransom for all, which is the testimony given at the proper time.” - 1 Timothy 2:5–6

God commanded Israel not to acknowledge other gods, since He was the Savior who rescued them from Egypt, and thus it would be high treason to devote themselves to other deities (Ex. 20:1–3). But the Lord also gave the first commandment because He is actually the only God who is. Even those, like Cyrus the Great, who think they are serving other gods are actually serving Yahweh, the covenant Lord of Israel, albeit without receiving salvation (Isa. 45:1–7). All people are going to serve the plans of God in one way, shape, or form, and it makes far more sense to exalt the one, true God and shun all other deities than it does to elevate lesser gods. Only those who turn from these other gods will experience the Lord’s gracious redemption. Like every other element of the old covenant, the first commandment is fulfilled ultimately in Christ. Old covenant Israel was supposed to learn that since there is only one God, there is only one way of salvation — only one way of access to Him (Isa. 43:11). This should have been clear enough from the old covenant revelation, but Israel’s tendency to think of Yahweh as one among many gods, which gods could help the Israelites at certain times, shows just how many in the old covenant community misunderstood God’s message.
In sending His Son, however, the Father has shown us even more clearly that there is only one way of salvation and, therefore, only one God who is able to redeem creation. This is one of the points of today’s passage. Paul is saying to an audience living in a culture with many “ways of salvation” that the practical application of monotheism is that the Father alone determines the means by which He is reconciled to sinners. His choice? The sending of His Son to reveal His grace and embody the one avenue of redemption (1 Tim. 2:5–6). Since God is the only God, He transcends all ethnic, national, and sociological barriers. There is to be no worrying about other means of salvation, for the one God offers a universal promise that all who come to Him through the one way, truth, and life will be redeemed. Those who affirm many ways of salvation really affirm the existence of many gods with many standards, which is foolish given that no other gods exist. The one God has revealed in the one Mediator the one way of salvation, and only the fool would seek redemption elsewhere.