For He has spoken in a certain place of the seventh day in this way: “And God rested on the seventh day from all His works”; and again in this place: “They shall not enter My rest.” 

Since therefore it remains that some must enter it, and those to whom it was first preached did not enter because of disobedience, again He designates a certain day, saying in David, “Today,” after such a long time, as it has been said: “Today, if you will hear His voice, Do not harden your hearts.” Hebrews 4:4-7 NKJV