10 And the Lord said unto Moses, Go unto the people, and sanctify them to day and to morrow, and let them wash their clothes,

11 And be ready against the third day: for the third day the Lord will come down in the sight of all the people upon mount Sinai.

Already we heard how the Israelites expressed their intent to do all that the Lord commanded them, and He had responded by saying that He would let them hear His voice directly. Before that could transpire, though, they had to go through a purification process. Much as how Moses had been commanded to put the shoes off his feet at the burning bush, the Israelites now needed to wash their clothes. This was a time for removing the dirt and the dust, the particles of the earth, in order to have as little of the world between them and the Lord when he arrived.

We will hear in the coming verses that the people were also instructed to not be sexually active during this period of three days. Thus this was also to be a time of fasting from the basic desires and habits of the flesh, a time of enhancing the spirit within. Their spirits had to be ready to meet the Lord’s spirit, their hearts had to be open to His heart, their will had to be subservient to His will. Only then would they be ready to receive His word as it needed to be received.