Christians need the grace of God to overcome sin. There is no way that the Christian can do any single moment without the grace of God. Ephesians 2:8-10 shows how the grace of God works as salvation has never been about one's self but by the grace of God. A Christian is saved by grace through faith - it is not of themselves, it is a gift of God so no man could boast. There is no boasting in the Christian life even in doing good works. God ordains His elect unto good works and the good works come out as part of the new nature. Titus 2:11-14 says that the grace of God results to good works. James 2:14-24 shows the truth that true faith will result to good works. Any kind of faith devoid of good works is not a real faith. Any kind of doctrine that teaches grace without resulting to any change is not grace at all.
The grace of God is through the Lord Jesus Christ. 1 Timothy 2:5 says that there is only one Mediator between God and man, that is the Lord Jesus Christ. We have human mediators in conflicts but they cannot be the one who brings man and God close together. To teach there there is any other mediator between God and man is a lie from the pits of Hell. When a pastor prays for somebody, that is not an act of mediation in the sense of trying to reconcile God and man. Christ is the only Mediator between Christians and the Father. Mary though she is important in fulfilling prophecy is not as important as the Lord Jesus Christ. Mary is a fallen sinner saved by grace, Jesus is the eternal Son of God. Roman Catholics may say they believe 1 Timothy 2:5 and try to beat around the bush but trying to put another Mediator between God and man is really absolute blasphemy. Mary is also dead and cannot hear the prayers of the living.
Christian life is built on Sola Scriptura not Solo Scriptura. To have Sola Scriptura means to have the Bible as the only guide to filter everything and not to only read from the Bible. Reading the Bible one time does not make one an expert. We do need sound Christian literature to help us further understand the Bible. Christians can know which are true and which are false teachings when they use the Bible as a filter. The more I read the Bible verse by verse, the more I see something is wrong with a lot of so-called Christian authors. Satan misquoted Scriptures, Jesus took them in context during the temptation in the wilderness. As Charles H. Spurgeon says, "Read many books but live the Bible." Good Christian books may help us understand the Bible better but they are not free of error so use the Bible as a filter for truth.
The motivation of the Christian is glory to God alone. If anybody does good works hoping to attain salvation then that person is not doing it for the greater glory of God but for the greater glory of self. Any Christian can freely use the phrase "For the greater glory of God." while those who only seek their personal glory in God's name do not deserve to use it. When a good work is done by the Christian it is wholly for the glory of God that He may be glorified. It is let your light shine before men so they may glorify God and not let your light shine so they may glorify you (Matthew 5:16). The Pharisees only did acts of righteousness to be praised by men but Christians do good works only because of their genuine faith and the grace of God working in their lives.