1 John 5:20
And we (have seen and) know (by personal experience) that the Son of God has (actually) come (to this world), and has given us understanding and insight so that we may (progressively and personally) know Him who is true; and we are in Him who is true-in His Son Jesus Christ. This is the true God and eternal life.

A person who receives the salvation of Jesus is first presented with the redemptive truth. They need to know the why of salvation and the truth of Jesus that releases them from sin; otherwise, salvation means nothing without truth. The truth explains the benefits of belief in Jesus Christ of salvation, love, health, and protection.