“For the Law was given through Moses; grace and truth were REALIZED through Jesus Christ.”
John 1:17 New American Standard Bible (NASB)
Most translations of John 1:17 say “grace and truth CAME by (or through) Jesus Christ” as if Grace or Truth didn’t exist before Jesus. It is not that Grace didn’t exist in the Old Testament, it is that we couldn’t receive God’s Grace. God has always had Grace toward humanity, he was never angry with us, the problem was with us.
The sin (error) of Adam created a break in the relationship (separation) between God and us. The sacrifice of Jesus demonstrated God’s love and goodwill for us and corrected the break (sin) in our relationship with God.
The act of dying on the cross by Jesus has forgiven (healed) every single human being: past, present, and future. This unconditional forgiveness (GRACE) means there is no longer a break in the relationship between us and God. Everyone is forgiven (healed from sin) but not everyone has realized it or is experiencing it.
Grace means Favor or Approval. The Grace that God gives is that his Favor, Acceptance, and Blessing is no longer at a distance. He shows Approval, Pleasure, and Delight in all of his children. He has nothing but Good Will, Affection, and Benefit for all of us.