I'm slowly reading through Robert Haldane's Exposition of the Epistle to the Romans. Currently, I'm studying Romans 10 verses 1 through 12, and I find Mr. Haldane's comments helpful in light of my book study through Jeremiah Burroughs' Faith.
Mr. Haldane defines faith as the only "appointed medium or means of our union with Christ, through which we receive this righteousness [Rom. 10:10], and not the righteousness itself," (p. 507). "Justifying faith is the belief of the testimony of Christ, and trust in Him who is the subject of that testimony. It is believing with the heart...Faith is necessary to obtain the gift of righteousness. Confession is necessary to prove that this gift is received. If a man does not confess Christ at the hazard of life, character, property, liberty, and everything dear to him, he has not the faith of Christ. In saying, then, that confession is made unto salvation, the Apostle [Paul] does not mean that it is the cause of salvation, or that without it the title to salvation is incomplete. When a man believes in his heart, he is justified. But confession of Christ is the effect of faith, and will be evidence of it at the last day," (p. 508). "Faith does not save us by being strong or weak. It is Jesus Christ by whom we are saved; and not by our faith, which is only the instrument or hand by which we receive him," (p. 509).
"That if thou shalt confess with thy mouth the Lord Jesus, and shalt believe in thine heart that God hath raised him from the dead, thou shalt be saved. For with the heart man believeth unto righteousness; and with the mouth confession is made unto salvation. For the scripture saith, Whosoever believeth on him shall not be ashamed," (Rom. 10:9-11).