"Can't complain, and it wouldn't do any good if I did." The old saw is true, and good to remember. However, according to the Psalmist, it tells only half the story.
"I complained, and my spirit was overwhelmed" (Psalm 77:3).
Words of murmuring and discontent are actually harmful to us in the innermost depths of our being. "Keep thy heart with all diligence, for out of it are the issues of life" (Proverbs 4:23). Complaint is a dangerous foe against which we must always be on guard if we do not want our spirits to be ransacked and overrun with fear, sorrow, and anger. It is also an evidence that the enemy is already at the gate, as it were, and has begun the intrusion that can lead to spiritual weakness and paralysis.
"Thou wilt keep him in perfect peace, whose mind is stayed on Thee, because He trusteth in Thee" (Isaiah 26:3).
Complaint is always a clear indication that we are not thinking rightly about our God, and responding to circumstances, situations, and conditions rather than the spirit and truth of the Lord Jesus Christ. The remedy for complaining, therefore, is not the determination to avoid complaining because of its lack of benefit, or even because it does harm. The remedy is repentance, or the change of mind whereby we determine to consider our lives in the light of Christ's life. Who is He? What has He done? What is He doing? And what does He promise to do in this moment and forevermore for those who have believed? Growth in this grace and knowledge of the Lord Jesus will go far in replacing the grumbling of discontent with the glad affirmation of joy and peace.
"Death and life are in the power of the tongue."