Why do Christians still sin?

We are born sinners. Before we’ve done anything we are one thing, sinful. Praise God, He gives life to us so that we repent and believe. Our sins- past, present and future- are forgiven. Why though are there future sins? When He declares us, in Christ, to be righteous, why does He not make us righteous fully and immediately?

It’s not a question we ask ourselves often enough. I suspect such is because we are comfortable with our sin. Believers, however, have not only been born again, not only been given a love for His Word, are not only indwelt by His Spirit but are also being washed by Jesus Himself (Ephesians 5). But we still sin.

At the horizontal level we still sin because while our old nature is dead in one sense, in another it is being put to death, and thus still lives. We are in a battle because sin, while its reign over us has ended, still has influence on us. We are, as Martin Luther put it, simul justis et peccatore, at the same time just and sinner. This battle will come to its conclusion either when He returns or when we go to Him. For now, we sin because we choose to sin. It is frustrating, maddening, humiliating. See Paul’s struggle at the end of Romans 7 for a powerful picture of the anguish that walks with us through our days.

At the vertical level, remembering that God is not guilty of any sin, especially our own, we must also acknowledge that God is sovereign even over our sins. If He ultimately wished them not to be, on the other hand, they would not be. What reason could He possibly have for allowing sin to continue in us? His glory and our good.

When teaching through Romans 7 recently it struck me that it might be that the thorn in Paul’s side that he prayed so fervently that it would be removed might not be a physical ailment. (I’ve long held, based on the description, “thorn in the side” and the fervency of the prayer that it had to be kidney stones) might be instead a besetting sin that he struggled with. If it were, it would fit snugly with God’s answer as to why He didn’t remove it. He wanted Paul to remember his dependence on God’s grace. Let us here heed the warning of Paul. We don’t excuse our sin this way, suggesting that we sin all the more that grace might abound (Romans 6:1). Nevertheless, our ongoing sins provide ongoing reason for the believer to run to the Father, to repent, and to rejoice in the forgiveness we have in Christ, glorifying God.

We are commanded to mortify our flesh, to fight the good fight, to own our sin. Nothing above should serve as an excuse for sin, nor do anything to lighten the weight of our repentance. But we need not be puzzled over why He hasn’t determined to end our battles on this side of the veil. He is glorified in every victory, and, as we run to Him seeking His mercy, every defeat.