The people want to make sure that they are going to follow the Word of the Lord in their worship. They are going to actually have God regulate how they worship, which is common sense. If God is the One who commands us to worship him, then we ought to worship in the way that God commands, right?
So, worship is not just making up your own ideas, doing your own thing, and being as creative as possible. In fact, when people have tried to be creative in worship, it usually did not go well with them. Nadab and Abihu are a case in point; they wanted to offer strange fire before the Lord. In other words, they wanted to offer incense that had not been prescribed by God. It might seem like a small thing, but of course, God actually killed them right there (Leviticus 10:1–3). And so God is not only the One who commands us to worship him, but God is the One who commands how he should be worshipped.1
Brian Borgman
2 Josué, fils de Jotsadak, avec ses frères les sacrificateurs, et Zorobabel, fils de Schealthiel, avec ses frères, se levèrent et bâtirent l'autel du Dieu d'Israël, pour y offrir des holocaustes, selon ce qui est écrit dans la loi de Moïse, homme de Dieu.