Here is an excerpt:
It is very important that we take time to prepare our hearts to worship God before we set foot in the sanctuary on Sunday morning. God made this clear amid the awesome circumstances of the giving of the law in Exodus 19. God called the people to prepare to come into His presence, or near His presence, but not actually onto the mountain where He would speak to Moses. “Then the LORD said to Moses, ‘Go to the people and consecrate them today and tomorrow, and let them wash their clothes. And let them be ready for the third day. For on the third day the LORD will come down upon Mount Sinai in the sight of all the people’” Ex. 19:10–11. God wanted the people of Israel, before they came near to Him, to get ready to come near to Him, to prepare themselves for an encounter with Him.