To doubt the lovingkindness of God, is thought by some to be a very
small sin; in fact, some have even exalted the doubts and fears of God’s
people into fruits and graces, and evidences of great advancement in
experience. But to doubt the kindness, the faithfulness, and the love of
God, is a very heinous offence. That can be no light sin which makes God
a liar; and yet unbelief does in effect cast foul and slanderous
suspicion upon the veracity of the Holy One of Israel. That can be no
small offence which charges the Creator of heaven and earth with
perjury; and yet, if I mistrust His oath, and will not believe His
promise, sealed with the blood of His own Son, I count the oath of God
to be unworthy of my trust; and so I do, in very deed, accuse the King
of Heaven as false to His covenant and oath. Besides, unbelief of God is
the fountain of innumerable sins. As the black cloud is the source of
many rain-drops, so dark unbelief is the parent of many crimes. It is a
sin which should be condemned by every believer, should be struggled
against, should if possible be subdued, and certainly should be the
object of our deep repentance and abhorrence.