For zeal to be true biblical zeal, it must conform to the mind of Christ. It most certainly must be in accord with God’s Word. According to J. C. Ryle:
“It is always good to be zealous in a good cause.” (Galatians 4:18)
There is such a thing as zeal from more selfishness. There are times when it is men’s interest to be zealous in religion. Power and patronage are sometimes given to godly men. The good things of the world are sometimes to be attained by wearing a cloak of religion. And whenever this is the case, there is no lack of false zeal. Such was the zeal of Joab, when he served David. Such was the zeal of only too many Englishmen in the days of the Commonwealth, when the Puritans were in power.
There is such a thing as zeal from the love of praise. Such was the zeal of Jehu, when he was putting down the worship of Baal. Remember how he met Jonadab the son of Rechab, and said, “Come with me, and see my zeal for the Lord.” Such is the zeal that Bunyan refers to in Pilgrim’s Progress, when he speaks of some who went “for praise” to mount Zion. Some people feed on the praise of their fellow creatures. They would rather have it from Christians than have none at all.
Ah! Reader, it is a sad and humbling proof of man’s corruption, that there is no degree of self-denial and self-sacrifice to which men may not go from false motives. It does not follow that a man’s religion is true, because he “gives his body to be burned,” or because he gives his “goods to feed the poor.” The Apostle Paul tells us that a man may do this, and yet not have true charity. It does not follow because men go into a wilderness, and become hermits, that therefore they know what true self-denial is. It does not follow because people immure themselves in monasteries and nunneries, or become sisters of charity, and sisters of mercy, that therefore, they know what true crucifixion of the flesh and self-sacrifice is, in the sight of God. All these things people may do on wrong principles. They may do them from wrong motives—to satisfy a secret pride and love of notoriety—but not from the true motive of zeal for the glory of God! All such zeal, let us understand, is false. It is of earth, and not of heaven. (“Be Zealous”)