Why sayest thou, that thou art righteous by faith only?

Not that I am acceptable to God, on account of the worthiness of my faith; but because only the satisfaction, righteousness, and holiness of Christ, is my righteousness before God; (a) and that I cannot receive and apply the same to myself any other way than by faith only. (b)

(a) 1 Cor.1:30 But of him are ye in Christ Jesus, who of God is made unto us wisdom, and righteousness, and sanctification, and redemption: 1 Cor.2:2 For I determined not to know any thing among you, save Jesus Christ, and him crucified. (b) 1 John 5:10 He that believeth on the Son of God hath the witness in himself: he that believeth not God hath made him a liar; because he believeth not the record that God gave of his Son.