And his disciples remembered that it was written, The zeal of thine house hath eaten me up. (John 2:17)
A warm fire is generated not by the kindling which is its fuel but by the match laid to the wood. So too, in a believer's life - the doctrines, creeds, and practices of the Scripture may be familiar. Every word spoken from a pulpit, a friend, a book, or a counselor proclaims within your heart, "I know that." But my brethren, is it not one thing to possess all the kindling but never lay the match to the wood? Doctrines, creeds, and practices must be engaged (engrafted) with heart and soul. They that worship him must worship him in spirit and truth (John 4:24). Daily we must bestir ourselves, not being content with an intellectual comprehension of truth only, making it our business to engraft the truth in our souls. Truth must become us! Truth adorned in the beauty of holiness! Truth clothed in a changed life! And when the Scripture becomes the living oracle through us then our hearts will be ignited with the love of Christ and His zeal. Apathy and coldness never converted anyone.
Success in religion depends on zeal, fervor. Cold preaching never does any good. Cold prayers are not answered. Cold efforts effect nothing. On the contrary, the simplest ministry of God's truth if fervent is powerful. A fervent people are always prosperous. Their deep sympathies melt the hardest heart. God's most honored instrumentality is such a people. Preacher and people together burning with the love of Christ and of souls constitute the favored instrumentality. This is irresistible; it makes the word irresistible through the Spirit. (Olin)