The Canaanites sinned greatly against the Lord and would not repent. Therefore, He commanded Moses to command Joshua to destroy the peoples,

But as for the cities that stood on their mounds, Israel burned none of them, except Hazor only, which Joshua burned. And all the spoil of these cities and the livestock, the children of Israel took as booty for themselves; but they struck every man with the edge of the sword until they had destroyed them, and they left none breathing. As the Lord had commanded Moses his servant, so Moses commanded Joshua, and so Joshua did. He left nothing undone of all that the Lord had commanded Moses (Joshua 11:13–15).

The last two sentences say it all. The Lord commanded Moses, who in turn commanded Joshua, and he did everything that Moses commanded, which means Joshua obeyed the Lord.

Likewise, the Lord has commanded the apostles to command us to do certain things. Are we doing those things?