Question: "What does the Bible say about ingratitude/unthankfulness?"
Answer: The Bible says much about gratitude as well as the lack of it. God knows how we are made, and He designed us to thrive when we are humble, moral, and thankful. When we are arrogant, immoral, and ungrateful, we cannot have fellowship with Him, nor can we experience all it means to be created in the image of God (Genesis 1:27; James 4:6; 1 Peter 5:5). So God included repeated commands in His Word about being thankful, reminding us that a grateful heart is a happy heart (1 Thessalonians 5:18; Colossians 3:15; Psalm 105:1).
Ingratitude is a sin with severe repercussions. Romans 1:18–32 gives a detailed description of the downfall of a person or a society. Listed alongside idolatry, homosexuality, and every kind of rebellion is unthankfulness. Verse 21 says, “Although they knew God, they neither glorified him as God nor gave thanks to him.” This tells us that God takes gratefulness—and ungratefulness—seriously. As long as a person or a culture remains thankful to God, they retain a sensitivity to His presence. Thankfulness toward God requires a belief in God at the very least, and ingratitude fails to fulfill our responsibility to acknowledge Him (Proverbs 3:5–6; Psalm 100:4). When we refuse to be thankful or to express gratitude, we grow hard-hearted and proud. We take for granted all God has given us and become our own gods.
Jesus’ healing of the ten lepers gives an example of how highly God values thankfulness (Luke 17:12–19). Jesus healed all ten men, but only one returned to thank Him (verse 15). The Bible specifically records that the thankful leper was not even a Jew. He was a Samaritan, a fact that drove home the idea that Jews were not the only people who could reach the heart of God. The Lord notices those who thank Him, regardless of socio-political status or level of spirituality. His questions “Were not all ten cleansed? Where are the other nine?” (verse 17) show His disappointment at the ingratitude of the majority.
Second Timothy 3:2 describes what people will be like in the last days, and one characteristic is ingratitude. When pride and self-rule become fashionable, the human heart has no one to thank. We become convinced of our own supremacy and consider all we have as a just reward for our efforts. We are wise to heed Paul’s rhetorical questions “What do you have that you did not receive? And if you did receive it, why do you boast as though you did not?” (1 Corinthians 4:7).
Ingratitude toward God is not so much a cause of evil but the result of it. Once we have hardened our hearts to the point that we no longer see God as the source of our gifts, nothing is off-limits. We become a law unto ourselves. One reason the Bible takes such a strong stance against unthankfulness and ingratitude may be that God knows that the end result of such arrogance is a reprobate mind (Romans 1:24). When we remind ourselves often that all we are and all we have is a gift from God (James 1:17), we are guarding ourselves against idolatry and pride.