Exodus 5:8

And the tale of the bricks which they did make heretofore ye shall lay upon them; ye shall not diminish aught thereof, the Israelites were to make and to deliver to the Egyptian overseers the same number of bricks as had always been required of them; for they be idle; therefore they cry, saying, Let us go and sacrifice to our God. Thus Pharaoh ascribed their request to be allowed to worship their God to a lack of sufficient occupation, to the fact that time was hanging heavy on their hands.