Therefore - As the result of the previous train of argument.
That a man - That all who are justified; that is, that there is no other way.
Is justified by faith - Is regarded and treated as righteous, by believing in the Lord Jesus Christ.
Without the deeds of the law - Without works as a meritorious ground of justification. The apostle, of course, does not mean that Christianity does not produce good works, or that they who are justified will not obey the Law, and be holy; but that no righteousness of their own will be the ground of their justification. They are sinners; and as such can have no claim to he treated as righteous. God has devised a plan by which, they may be pardoned and saved; and that is by faith alone. This is the grand uniqueness of the Christian religion. This was the special point in the reformation from popery. Luther often called this doctrine of justification by faith the article upon which the church stood or fell - articulus stantis, vel cadentis ecclesiae - and it is so. If this doctrine is held entire, all others will be held with it. If this is abandoned, all others will fall also. It may be remarked here, however, that this doctrine by no means interferes with the doctrine that good works are to be performed by Christians. Paul urges this as much as any other writer in the New Testament. His doctrine is, that they are not to be relied on as a ground of justification; but that he did not mean to teach that they are not to be performed by Christians is apparent from the connection, and from the following places in his epistles: Romans 2:7; 2 Corinthians 9:8; Ephesians 2:10; 1Ti 2:10; 1 Timothy 5:10, 1Ti 5:25; 1 Timothy 6:18; 2 Timothy 3:17; Titus 2:7, Titus 2:14; Titus 3:8; Hebrews 10:24. That we are not justified by our works is a doctrine which he has urged and repeated with great power and frequency. See Romans 4:2, Romans 4:6; Romans 9:11, Romans 9:32; Romans 11:6; Galatians 2:16; Galatians 3:2, Galatians 3:5,Galatians 3:10; Ephesians 2:9; 2 Timothy 1:9.