Joshua said to the people, Sanctify yourselves; for tomorrow Yahweh will do wonders among you.
The people’s self-consecration (Joshua 3:5) consisted of their turning their hearts to God and getting their attitudes and actions right with Him (cf. Matthew 3:2; Matthew 4:17). God had previously promised to do wonders (Joshua 3:5, awesome miracles) when they would enter the land (cf. Exodus 34:10). Undoubtedly the people had been looking forward to seeing these miracles in view of what their parents had told them and what some of them remembered about the plagues in Egypt.