On the other hand, Nadab and Abihu, in their rebellion and contempt for God, displayed hearts totally at odds with his purposes. Their heart disobedience motivated them to knowingly offer incense with strange fire before God and this utter disregard for Yahweh and his law resulted in their violent deaths. As far as God is concerned, the heart that despises what he wants is wrong. It is led to disobedience and rebellion even when it seems, from all outward appearances, to be compliant. On the other hand, the heart that desires God's will and is always responsive to him even when it is unable to do what is required, is honored as right by God.
Some clarifications are in order.
Neither circumstance in this passage cancels out the other. Both are valid. And so for a well balanced understanding of what Yahweh wants from us, it is essential that we have a good grasp of two very basic principles. First, these two events clearly point to the fact that obedience or responsiveness to God is always a crucial issue requiring serious-minded consideration. It is a life and death issue and must continually be approached with that in mind.