The generation in the wilderness were not worse complainers than any other collection of human beings. Every association of human beings seems to be vexed by the ceaseless grumbling of the members.
The Torah says, "Now the people became like those who complain of adversity in the hearing of the LORD." (Numbers 11:1) God is slow to anger-usually. Complaining can incite His swift wrath. The book of Numbers contains several stories of Israel's discontent in the wilderness. In each story, the Israelites complain about something and God punishes them for complaining.
Human beings are prone to complain. It often seems that people are not happy unless they find something to be unhappy about. Nothing seems to please us more than complaining about what we don't like and what things do not meet our approval. We are malcontents.
A person of faith is duty bound to rise above the natural human instinct to complain and criticize.
Every day of our lives is full of both good things and bad things. Every human being has positive characteristics and negative characteristics. If we concentrate on the bad things that each day contains and the negative characteristics that each person possesses, we will spend our entire lives in an ugly world where everything goes wrong all the time and everyone we know is grossly deficient. With our critical spirits and tongues we can actually ruin our own lives.
Paul encourages us to "do all things without grumbling or disputing" (Philippians 2:14). Complaining is a form of evil speech (lashon hara). It has evil results in our lives and in the lives of others. Nobody wants to be around a chronic complainer.
A critical person complains against God. The Didache warns that grumbling and complaining is a symptom of a haughty spirit and that it can lead to blasphemy:
My child, do not be a murmurer, because it leads to blasphemy; neither be self-willed nor evil-minded, for out of all these blasphemies are engendered. But be meek, since the meek shall inherit the earth. Be long-suffering and merciful and genuine and gentle and good and always trembling at the words which you have heard. (Didache 3:6-8)
Grumbling about things is a telltale sign of weak faith. A person of strong faith has confidence that God is in charge and is working all things out for the good. He is not given to complaining because he believes that everything is ultimately in God's hands.
The antidote for a poisoned, malcontented spirit is gratitude. When we force ourselves to focus on the good and the positive, and to thank God for all the blessings He daily bestows, the way we experience life is transformed. But we should not thank God only for the good things. We should thank Him for everything, as Paul says, "In everything give thanks; for this is God's will for you in the Messiah Yeshua" (1 Thessalonians 5:18).
Judaism teaches that there is even a blessing for when one hears bad news: "Blessed is the true judge."
Paul urges us to not to "grumble, as some of them did [in the wilderness], and were destroyed by the destroyer. Now these things happened to them as an example, and they were written for our instruction" (1 Corinthians 10:10-11).