Exodus 19:10 - Wesley's Explanatory Notes

Sanctify the people — As Job before sent and sanctified his sons, Job 1:5. Sanctify them, that is, call them off from their worldly business, and call them to religious exercises, meditation and prayer, that they may receive the law from God's mouth with reverence and devotion. Two things particularly were prescribed as instances of their preparation. 1st, In token of cleansing of themselves from all sinful pollutions, they must wash their clothes. Not that God regards our clothes, but while they were washing their clothes, he would have them think of washing their souls by repentance. It becomes us to appear in clean clothes when we wait upon great men; so clean hearts are required in our attendance on the great God. 2dly, In token of their devoting themselves entirely to religious exercises upon this occasion they must abstain even from lawful enjoyments during these three days, and not come at their wives.