Christ is the ground of our righteous standing before God, our acceptance before Him. If we are properly equipped we can rest secure that our heart, our emotions, are securely guarded and adequately protected against attack.
This is perhaps the most frequent ground of attack against our faith. We can be made to feel like we lack assurance; we feel unworthy of God. We feel they we are failures in our Christian walk and that God is certain to reject us, that He is no longer interested in them. We are so aware of our failures and shortcomings. Growth has been so slow. The first joy of faith has faded, and we feel that God is estranged from us. There is a constant sense of guilt; our conscience is always stabbing them, making them unhappy. This is simply a satanic attack.
How do we answer such an attack? We must equip ourselves spiritually to withstand satanic attacks. We don’t stand on our own merits—we can’t. We never had anything worthwhile in ourselves to offer to God. We come to Him on His merit, on the ground of His imputed righteousness. We still stand before God on that basis.
Paul used this spiritual equipping when he was under pressure to be discouraged and defeated. Here was a man who was small of stature and unimpressive in his personal appearance. His background was anti-Christian, and he could never get away from that completely. He had been a most hostile, brutal persecutor of the Church. He was often reminded by many people that he was not one of the original apostles, that his calling was suspect, that he really wasn’t an apostle at all.
What a ground for discouragement! How easy it would have been for him to say, “What’s the use? Here I am working as hard as I can, making tents and trying to preach the Gospel to these people, and look at the blessing God has brought them, but they don’t care. They hurl recriminations back into my face. Why try anymore?” But that is not what he does.
Instead, Paul says, “But by the grace of God I am what I am, and his grace toward me was not without effect (I Corinthians 15: l0a).” He’s using the spiritual equipment Christ has made available to us all. “I don't care what I have been; I don't defend what I am. I simply say to you, by the grace of God, I am what I am. What I am is what Christ has made me. I'm not standing on my righteousness; I'm standing on His. I am accepted by grace, and my personal situation does not make any difference at all.” So Paul’s heart was kept from discouragement.