“stretch out your heart to God.” Joshua is using a strong active verb to encourage the people. They must put away their pagan gods, to which they would have certainly been attached for various reasons, and then stretch out their hearts to Yahweh. We often speak of people having to “stretch themselves” when they are doing something unfamiliar or difficult, and that is the case here. The people had not been single-hearted toward Yahweh, and now they must stretch themselves to be that way.