The writer is drawing a parallel between a rest that Israel received and the rest promised to us. When Israel escaped slavery in Egypt and entered a land which was theirs, they looked forward to that rest. While on their way, some turned away from God and were never allowed to enter. We are warned not to turn away. Those who reject God鈥檚 offer of salvation will not enter his rest. The writer quotes David referring to rest as something that would come in the future. Israel was already living in their land when David wrote, so the rest he was talking about was even greater than the one they already had. The Jewish readers would have been familiar with Israel鈥檚 lack of faith and not being allowed to enter their land. They are being challenged not to make an even bigger mistake. If they reject Jesus, they will miss out on an even better rest. Jesus is then referred to as our High Priest. It was the duty of the High Priest to make sacrifices for the sins of the people. Jesus was similar to the High Priest because he sacrificed himself for our sin, but was different because he was sinless.
Another part of the parallel to Israel entering their rest is that they needed to work in the present before entering rest in the future. Our lives here on earth are hard work. We suffer opposition, need to work to provide for ourselves and strive to keep moving forward spiritually. The rest comes when we enter the arms of our Savior!