William Ames’ The Marrow of Theology (first published in 1623) has two main parts that can be described in a few ways: doctrine and ethics, theoretical and practical theology, or faith and life. Ames opens the second section on ethics/life/practical theology with a discussion on Christian obedience called “Observance in General.” Here are a few notes from his discussion. Note especially his words on faith and the law of God.
“Observance is the submissive performance of the will of God for the glory of God. It holds the will of God as a pattern and a rule, as shown by the words of Christ which both describe our observance (Mt. 6:10) and explain his own (Mt. 26:39, 42).”
“Observance…is concerned with the [revealed] will of God which prescribes our duty (Deut. 29:29). It means that our will is submissive (Rom. 8:7).”
“Observance looks to the glory of God. It is said to be towards God, for he is at once its standard, its object, and end.”
“The principle efficient cause of observance as an inner, abiding principle is indirectly faith and directly sanctifying grace.”
“Faith brings forth obedience in three ways: First, it apprehends Christ who is the fountain of life and the spring of all power to do well. Second, it receives and acquiesces in the arguments which God has set forth in Scripture to induce obedience, namely, promises and threatenings. Third, it has the power to obtain all grace, especially that grace which occasions obedience.”
“Our observance is nothing else than gratitude owed to God, and is rightly explained by theologians under that title.”
“The law of God …does not have the justifying power it had in the original state of integrity nor the condemning power it had in the state of sin. But it does have the force and vigor of a directing power; and it also retains a certain force of condemnation, for it reproves and condemns sin in the faithful (although it cannot wholly condemn the faithful themselves because they are not under the law but under grace.)”