"Grumbling is a gauge of the human soul. It gauges our gaze on grace. It tells us that we’re not seeing grace.
…Grumbling is a symptom of a myopic soul. Selfishness has caused tunnel vision and has fixated on a craving(s). The soul has lost sight of the glory and wonder and splendor and hope that is the reborn, redeemed life and thus it is far too easily displeased. Grumbling is evidence of soul-vision impairment.
The opposite of grumbling in the soul is gratitude.
…Gratitude is a symptom of a healthy, expansive soul. The gospel of grace has given it panoramic vision, allowing it to see that this grace will be sufficient (2 Corinthians 12:9) to meet every need (Philippians 4:19) when inconvenience, crisis, weakness, affliction, unexpected demand, suffering, and persecution hit. In fact, in all these things this grace will make us ‘more than conquerors through him who loved us’ (Romans 8:37).”