What is strange fire? According to typology, strange fire is any fire other than that which burns on the altar of burnt offering….To have strange fire is to have some kind of motive within us that is natural and that has not been dealt with by the cross. (Life-study of Exodus, p. 1638)
The altar is a type of the cross, whereas the incense is a type of our service before God. The zeal of our service must come from the altar of the cross.
The zeal of many is but strange fire! Men often do not go through the dealing of the cross; they do not reject their own will and wisdom, and they act according to their flesh. Yet they think that by so doing, they can please God and revive the Lord’s work. This is zeal to be sure, but it is not zeal that comes from God. It is fire to be sure; however, it is not fire from the altar but strange fire. Anything that is not from the altar of the cross of self-denial is strange fire. Strange fire is fire of the self; it is fire that issues from the soulish life, the fleshly life, and the natural life. Strange fire means that the self-life interferes with the works of God. Although the works are God’s, the self-life wants to dictate the way the works are carried out. Offering up strange fire is employing the self’s methods and wisdom and insisting on the self’s proposals in the works of God. Strange fire will not win us God’s acceptance in the incense of our service but will cause us to die before the Lord [Leviticus 10:1-2]. (Collected Works of Watchman Nee, vol. 38, pp. 358-359)