How do we know the Gospel is immutable?

The immutability of the Gospel stems from the unchanging character of God, as expressed in Malachi 3:6, 'For I am the Lord; I do not change.' The Gospel preached by Paul, Moses, and even in the Garden of Eden remains the same because it comes from God's eternal, unalterable truth. Therefore, the principles of repentance and faith, core to the Gospel message, have not and will not change. As Peter states in 1 Peter 1:25, 'The word of the Lord endures forever,' underscoring the Gospel's everlasting nature.