Complaining and griping because we are undergoing various hardships or because we lack something we very much want ends up undermining our spiritual progress. It leads to becoming discouraged (Prov 15:4, LB). This is why Oswald Chambers said, “If you have the whine in you, kick it out ruthlessly.”
Instead of toiling, by God’s strength, to bring our salvation and spiritual victory to greater completion (Phil 2:12-13), our focus when we complain is on the belief that the Lord is not a good, wise, and generous provider of whatever progress or victory we want right now (Phil 2:14). Naturally, God cannot bless such an attitude – so we find ‘confirmation’ of our negative view of Him. The resulting spiral of unbelief will lead to our ruin. Habitual complaining becomes bitterness (Heb 12:15, OSB note).
There is a place for offering complaints over legitimate wrongs by others so those after us might not have to suffer the same wrong. However, our normal way of complaining emphasizes the faults of others and what we don’t have so life would go as we wish (Jude 16, Phillips with Voice). Instead of engaging in the more common form of complaining, let us focus on our blessings and be thankful. After all, thankfulness is a natural result of being directed by God’s Spirit (Eph 5:18-20). Conversely, ingratitude and complaining are clear indications of unbelief (Rom 1:21). Complaining shows that we are focusing on our agenda, rather than His. It often does not involve real prayer with faith (Hos 7:14, CEV).
Instead of being timid, learn to be appropriately bold.