God created the heavens and earth in six days, made man in his own image, and on the seventh day Genesis 2 says he rested. He blessed the seventh day, made it holy, and rested. Everything but man was spoken into existence. He is infinite, almighty God; did one week of talking a lot really wear him out?
In the first place, the text doesn’t say he collapsed from exhaustion. There is a difference between dropping dead and taking a break. Rest is a gift. Recall that when criticized for breaking the Sabbath by doing good works Jesus points out that “the Sabbath was made for man, not man for the Sabbath.” (ref) One need not be on the verge of collapse to rest, but that’s still not even the point.
Hebrews is easy to preach because its form is much more like a sermon than an epistle (letter). At the heart of its message is an impassioned plea not to leave the Christian faith for another, and so in order to be convincing the author of Hebrews makes many comparisons between Christ and all the things of the Old Testament he is superior to. We have already seen that Christ is superior to the angels, and that through suffering he becomes the perfect founder of our faith. Chapter 3 begins this way:
Therefore, holy brothers, you who share in a heavenly calling, consider Jesus, the apostle and high priest of our confession, who was faithful to him who appointed him, just as Moses also was faithful in all God’s house. For Jesus has been counted worthy of more glory than Moses—as much more glory as the builder of a house has more honor than the house itself. (For every house is built by someone, but the builder of all things is God.) Now Moses was faithful in all God’s house as a servant, to testify to the things that were to be spoken later, but Christ is faithful over God’s house as a son. And we are his house if indeed we hold fast our confidence and our boasting in our hope. Hebrews 3:1-6