The initial covenant God made with mankind was a covenant of works. In this covenant, according to the Westminster Confession, “life was promised to Adam; and in him to his posterity, upon condition of perfect and personal obedience.” It is important to note that a “condition” is attached to this first covenant. The condition is personal and perfect obedience. This is a condition of works, and this is the covenant’s chief stipulation. Life is promised as a reward for obedience for obedience, for satisfying the condition of the covenant.
Sproul, R.C.; Grace Unknown: The Heart of Reformed Theology; Baker Books; Grand Rapids, MI; copyright 1997; p. 109