Grumbling is serious.
Consider the following examples:
When Israel murmured against Moses, they were in reality murmuring against God:
“…and what are we? your murmurings are not against us, but against the LORD” (Exodus 16:8).
At the edge of the promised land, Israel grumbled in unbelief and it cost them forty more years in the wilderness: “Your carcasses shall fall in this wilderness; and all that were numbered of you, according to your whole number, from twenty years old and upward, which have murmured against me. Doubtless ye shall not come into the land, concerning which I sware to make you dwell therein, save Caleb the son of Jephunneh, and Joshua the son of Nun” (Numbers 14:29-30).
The onlookers murmured when Mary of Bethany anointed Jesus with precious ointment: “And there were some that had indignation within themselves, and said, Why was this waste of the ointment made? For it might have been sold for more than three hundred pence, and have been given to the poor. And they murmured against her” (Mark 14:4-5).
The Pharisees and scribes murmured because Jesus received sinners: “And the Pharisees and scribes murmured, saying, This man receiveth sinners, and eateth with them” (Luke 15:2),
Judgment is coming for grumblers: “These are murmurers, complainers, walking after their own lusts…” (Jude 16).
The grumblers have been around in every age. Are you comfortable among them?