Hebrews 4:7 - Coke's Commentary on the Holy Bible

Again, he limiteth a certain day,— "The scripture mentions God's rest again, with a strong exhortation to the people in David's days; and he gives a strong encouragement to them not to harden their hearts: and even so many years after Moses was dead, he uses the expression to-day; which implies present time, and a rest different from that of Canaan, and what the faithful even then were to enjoy." Dr. Heylin renders this and the next verse more clearly thus: He again determines a certain time, called To-day; saying by David, so long after the words recited, To-day, since you heard his voice, harden not your hearts, Hebrews 4:8. For if Joshua had given them rest, David would not afterwards have spoken of another day. "The land of Canaan cannot be the true rest promised by God, because David speaks of a rest as still future, and to be acquired by such as were ready and willing, in his time, to hearken to the voice of God."