Norman Geisler provides an illustration of our tendency toward wandering from the truth of the gospel:
According to aeronautic experts, when a propeller-driven airplane takes off it naturally veers left unless it is steered right. Based on my observations of evangelical institutions and leaders over the past half century, it appears to me that the same principle applies. The only way to keep on the straight orthodox path is to keep turning to the right. Churches, schools, and even evangelical scholarship will naturally go left, unless they are deliberately turned to the right. The prevailing winds of doctrine blow against us. And if we are to resist them we must have a firm grip on the wheel of [the church] and steer it to the right.
 Norman Geisler, “Beware of Philosophy: A Warning to Biblical Scholars” Christian Apologetics Journal, Vol. 2 No. 1 (1999).