The people of God want to establish true worship, and their faithfulness in worshipping God is the best way to safeguard themselves from the dangers of their surrounding culture. So, did it take courage to build the altar? The answer is, yes, it took courage to build the altar because of course, there is going to be opposition, but understand they are building the altar because the best way to safeguard your own self, is to be safe in the true God.1
Brian Borgman
3 They set the altar in its place, for fear was on them because of the peoples of the lands, and they offered burnt offerings on it to the LORD, burnt offerings morning and evening.