Matthew Henry on Leviticus 10:12-20

Afflictions should rather quicken us to our duty, than take us from it. But our unfitness for duty, when it is natural and not sinful, will have great allowances made for it; God will have mercy, and not sacrifice. Let us profit by the solemn warning this history conveys. When professing worshippers come with zeal without knowledge, carnal affections, earthly, light, vain, trifling thoughts, the devices of will-worship, instead of the offering of soul and spirit; then the incense is kindled by a flame which never came down from heaven, which the Spirit of a holy God never sent within their hearts.