For the law was given by Moses, but grace and truth came by Jesus Christ. (John 1:17)
God doesn’t simply give grace as a THING, nor is grace merely descriptive of how He works. Rather, God gives us Himself. God IS, “the God of all grace,” the God whose nature is that of all grace. (I Peter 5:10)
When God gave us Jesus Christ, He gave us the One who is the sum of all of that He is – the sum of all grace and Truth. In Christ dwelt the fullness of God. (Col. 1:19)
How God works in Christ is therefore going to contain grace and Truth. All that God reveals is going to show that He is the God of all grace. All that the Holy Spirit manifests is going to reflect both the grace and Truth of the One the Holy Spirit always manifests: Jesus Christ. These are absolutes, for God cannot deny Himself. God is telling the Truth about Himself to us through His Son.