When you feel tired, the best you can do, is to rest. God knew/still knows that rest is very important. He created the sabbath as the day of rest and worship. He says that we have to remember the sabbath day to keep it holy. Neither us nor our helpers must work on the sabbath. We all have six days in a week to work, but on the seventh day, we must rest and worship God our Creator (Exodus 20:8-11).