Here are some great and comforting words by Cornelis Venema on faith alone (sola fide) and Christian obedience.
“For the Reformers, ‘faith alone,’ far from being detrimental to the Christian life of good works, is the only basis and source of Christian obedience. To place works before justification, as though they played a role in obtaining God’s acceptance, alters the character of the Christian’s life of obedience. Rather than good works being the fruits of thankfulness, which are born out of the grateful awareness of the believer’s acceptance by God, they are regarded as a means to obtain favor with God. If works are performed to obtain God’s favor, however, they are no longer performed in good faith. They become corrupted by a self-seeking desire to curry favor with God, or to wrest from God a reluctant acceptance and forgiveness.”
“According to the Reformers, the Christian’s freedom is a freedom to obey God, not a freedom to sin or continue in disobedience. However, the obedience of faith is not constrained by a fear of punishment or falling into disfavor with God. Rather, it is a joyful delight in God and his will, which springs from an awareness of God’s undeserved favor in Christ.”
“When justification undergirds the believer’s sanctification, Christian obedience is no longer colored by an anxious uncertainty regarding God’s grace. Calvin expresses this point in his comments on James and Paul, when he insists that we should not place good works, which are the inevitable effect of true faith, before faith, which is the only cause of good works. Unless believers are acceptable to God by faith in Christ, it is not possible for their works to be pleasing to him. At the same time, it is impossible for those who know the grace of free justification and who are united to Christ by faith, not to be renewed in good works.”
I suppose these paragraphs might be a helpful commentary on Heidelberg Catechism Q/A 91 and Westminster Confession of Faith 16:1-2.
The above quotes are found on pages 85-86 of The Gospel of Free Acceptance in Christ by Cornelis Venema.