This study begins with a discussion and evaluation of Calvin's teaching on saving faith and assurance of salvation, and then proceeds to relate the results of the evaluation to the development of Scottish teaching from the Reformation to the 19th century. Galvin presents saving faith as the certain persuasion of knowledge, the knowledge of God's love for me in Jesus Christ. He maintains that Christ died for all of mankind without exception. To have faith in Jesus Christ, therefore, is to have assurance of salvation. Thus, Jesus Christ is, for Galvin, the mirror of our election. By the 17th century, Scottish Calvinism had developed a Federal theology with alterations and even distortions of Calvin's thought. Unlike Calvin, the Federalists began their theological system with a discussion of the decrees of God, and moved logically from a double decree of predestination to that of a limited atonement. To this they added a twofold, and sometimes threefold covenant scheme wherein all mankind are by nature under the covenant of works, but only the elect are entered into the covenant of grace. The Federalists rejected, and their system excludes the possibility, that assurance is of the essence of faith. Assurance was to be acquired through a reflex act of faith whereby we examine ourselves for evidences of election. Federal theology of this period became very legalistic, and was characterized by conditional notions of grace. Thomas Boston and the Marrow men protested against the legalism of much of the Federal teaching, and argued that God's grace is unconditional, and that assurance is of the essence of faith. Their success was very limited, however, because they worked from within the Federal system, which itself was responsible for the problems they sought to correct. A century later, however, with John McLeod Campbell we return full circle to Galvin's position that assurance is of the essence of faith, and is so because God's love and grace for salvation is expressed fully in Jesus Christ, who made atonement for all mankind without exception.