May the Lord make each of us to be of his character! You may know him by his attachment to the Lord Jesus, who is the Sum, Substance, Surety, and Seal of the covenant. The committed believer is known also by his zeal of the Gospel, through which the covenant is revealed to the sons of men. He will not hear anything that is not according to the old Gospel, for he counts any other gospel to be a deadly evil. He is very fond of the word grace, and with grace itself he is altogether enamored.
The person who is in covenant with God cannot bear the idea of human merit–he loathes it. It raises his indignation. I have known some Christians who have come out from hearing certain apathetic sermons with their souls on fire with holy wrath. I feel, in casting my eye over many modern writings, as if I were about to die from breathing poisonous gas. We cannot endure the smell of false piety and human righteousness. Others may feed on philosophical morality, but nothing but the grace of God will do for us. Stray dogs may feed on any rubbish, but men of God must live on the grace of God and nothing else. Our keeping the covenant binds us to a firm adherence to the inspired Gospel and to the grace of God, which is the glory of it.
– Charles Spurgeon, from Grace: God’s Unmerited Favour