"nevertheless knowing that a man is not justified by the works of the Law but through faith in Christ Jesus, even we have believed in Christ Jesus, so that we may be justified by faith in Christ and not by the works of the Law; since by the works of the Law no flesh will be justified," (Galatians 2:16).
* There are only two means by which man may be eligible for heaven --- by earning it, or receiving it. Paul could not make it any clearer, that good deeds cannot, and will not, earn anyone entrance into heaven. The only means God has ordained by which man may be saved is by faith in the Lord Jesus Christ. And that very faith that saves is given by God, not earned by works.
* To be justified is to be declared righteous, and its opposite is to be condemned. Yet, since people are condemned sinners, and God is unspeakably holy, how can people be justified?
Paul's answer is as plain as possible --- by faith in the Lord Jesus Christ.