But as many as received Him, to them He gave the right to become children of God, even to those who believe in His name, who were born, not of blood nor of the will of the flesh nor of the will of man, but of God…
…for God so loved the world, that He gave His only begotten Son, that whoever believes in Him shall not perish, but have eternal life. For God did not send the Son into the world to judge the world, but that the world might be saved through Him.
For God's grace to have meaning in your life, you must receive it!
Of course, this is obvious in life, isn't it? Someone may buy you a gift that costs them a lot, and give it to you from their heart. But if you have some problem with them and don't accept or receive the gift, then the giving isn't complete. Likewise, it isn't enough that Jesus has died on the cross for you to purchase your forgiveness from God. Even though He offers you forgiveness, that forgiveness is not yours until you accept and receive it.
How do you do that? By faith. That is, let God know that you're choosing to trust in Jesus, that His death on the cross was an expression of God's grace for you. When you put your faith in Jesus, then the gift of forgiveness becomes yours.