Targum zu Kohelet 5:11

Sweet is the sleep of a man who serves the Lord of the world with all his heart; and he has rest in his grave, whether he lives few years or many years; after having served the Lord of the world in this world, he will inherit in the world to come a reward for the works of his hand. And the wisdom of the Law of God belongs to the man who is rich in wisdom; in the same manner as he occupies himself with it in this world, and exerts himself in learning, so will it rest with him in the grave, and not leave him alone; just as a woman does not leave her husband to sleep alone.