Quotes from his Romans Commentary:

"Paul revealed that Abraham had glory before God not because he was circumcised, nor because he abstained from evil, but because he believed in God." (On Rom 4:3)

"to somebody who is bound by sin and who therefore does not do what the law commands ... who believes in Christ without doing the works of the law, his faith is reckoned for righteousness just as Abraham’s was." (On Rom 4:5)

"Paul backs this up by the example of the prophet David, who says that those are blessed of whom God has decreed that, without work or any keeping of the law, they are justified before God by faith alone." (On Rom 4:6)

"How can these words apply to a penitent, when we know that penitents obtain the forgiveness of sin with much struggle and groaning? How can they be applied to a martyr, when we know that the glory of martyrdom is obtained by sufferings and pressures? But the prophet, foreseeing a happy time when the Savior comes, calls them blessed, because their sins are forgiven, covered and not reckoned to them, and this without labor or work of any kind." (On Rom 4:7)

"Obviously they are blessed, whose iniquities are forgiven without labor or work of any kind, and whose sins are covered without any work of penitence being required of them, as long as they believe." (On Rom 4:8)

"They are justified freely because they have not done anything nor given anything in return, but by faith alone they have been made holy by the gift of God. " (On Rom 3:24)

" To keep the law is to believe in Christ, who was promised to Abraham... For every mention of salvation in the law refers to Christ. Therefore the man who believes in Christ is the man who keeps the law. But if he does not believe then he is a transgressor of the law, because he has not accepted Christ, of whom the law prophesied with regard to the righteousness which was to come but which it could not itself give." (On Rom 2:13)

"whoever does not sin is a friend of the law. For him, faith alone is the way by which he is made perfect, for avoiding evil will not gain him any advantage with God unless he also believes in God, so that he may be righteous on both counts. The one righteousness is temporal, but the other is eternal." (On Rom 2:12)

"God has decreed that a person who believes in Christ can be saved without works. By faith alone he receives the forgiveness of sins." (On 1Cor1:4)

"Although Paul seems to be writing to the Romans in general, he specifies that he is really only writing to those who are in the love of God. Who are these people, if not those who believe the right things about the Son of God? They are the ones who are holy, and who are said to have been called. For someone who understands incorrectly is not said to have been called, just as those who act according to the law have not rightly understood Christ and have done injury to God the Father by doubting whether there is full salvation in Christ. Therefore they are not holy, nor are they said to have been called."

"Paul says this because those who hear the law are not justified unless they believe in Christ, whom the law itself has promised. This is what it means to keep the law. For how does someone who does not believe the law keep it, when he does not receive the one to whom the law bears witness? But the one who appears not to be under the law, because he is uncircumcised in his flesh, may be said to have kept the law if he believes in Christ. And he who says he is in the law, in other words, the Jew, is not a doer of the law but a hearer only, because what is said in the law does not penetrate to his mind, for he does not believe in the Christ who is written about in the law, as Philip said to Nathanael: We have found Jesus, of whom Moses in the law and also the prophets wrote." (On Rom 2:13)