Douglas W. Comin on Nadab and Abihu offering strange fire:
“Nothing should be more important and urgent to us than the worship of God, and no other consideration, however seemingly moving, should interfere with our performance of His required worship or induce us to lay aside what He has commanded.
Note also that the rest of the house of Israel… were to mourn, not so much for the tragic loss of their fellow Israelites, but for the offense which had been given to God, which had provoked His burning wrath. This command highlights the zeal that ought to be in the hearts of men for the glory of God, and the grief which ought to overwhelm every heart when God’s commands are set aside in favor of the presumptuous inventions of men.
How little of this mourning for giving offense to God exists among His people today! How little concern for the idea that what is done in the name of worship in so many churches has no warrant from the mouth of God! How little fear that man’s bold presumption in framing worship according to his own desires and interests kindles the wrath of the One who is to be regarded as holy and whose glory alone is to be magnified in the public assemblies of His people! Is it any wonder that the Church is so lifeless and impotent in the face of its enemies? She has forsaken her first and most urgent priority, and made the worship of the Holy God a mere show of the talents and ideas of men!
Surely the Church is under the judgment of God for its sins – chief among them being a disregard for the worship of God. If she is to be revived, and her glory restored, it must begin with bewailing the offenses she has given to God in worship.”
Read more and source: http://www.puritanboard.com/showthread.php/24182-Strange-Fire, Comment #19