We Could Not Be More Secure
The cross does not merely provide a temporary respite from condemnation. We are told that Christ stands before the Father as our legal representative, our advocate (1 John 2:2; Hebrews 7:25; Romans 8:33-34). What this means is that the law, once our enemy, which demanded our punishment, now becomes our friend, demanding our acceptance. How so? The law has been perfectly fulfilled in our substitute, and so now it would be unjust for God to turn on us! For God to punish us for any sin would be to exact two payments for the same debt (since Jesus has already paid it). Now Jesus stands before the Father, in a sense, demanding not mercy but justice for us. We have both his law and his love for us. We could not be more secure.
— Tim Keller, Forgive, page 81 (paid link)