Pretty simple: It is in the Bible. God commanded us to be content. What He gives us is enough. He gives us stuff but also gives us of Himself. Look at this verse in Hebrews about contentment.
Hebrew 13:5 Let your character be free from the love of money, being content with what you have, for He Himself has said, “I will never dessert your , nor will I ever forsake you.
If you are not content you are in sin. There I have said it. I have had to deal with this for a month you should have to deal it with for a morning. Sorry if that hurts your feelings. Another verse that speaks to this area of contentment is the 10th of the 10th commandments found in Exodus 20. This is one of the least talked about commandments but has much to say about contentment.
Exodus 20:17 You shall not covet your neighbor’s house. You shall not covet your neighbor’s wife, or his manservant or maidservant, his ox or donkey, or anything that belongs to your neighbor.
I didn’t grow up using the Catechism but the Westminster Shorter Catechism has some great insights into the 10th commandment.
Q80- What is required in the tenth commandment?
A80- The tenth commandment requires full contentment with our own condition, with a right and charitable frame of spirit toward our neighbor, and all that is his.
Q81- What is forbidden in the tenth commandment?
A81- The tenth commandment forbids all discontentment with our own estate, envying or grieving at the good of our neighbor, and all inordinate motions and affections to anything that is his.
William Barcley- A coveting spirit is a discontented spirit because it desires what God has not given to us. A contented spirit, on the other hand, finds delight in what God has provided.
We need to be happy or satisfied with what God has given us.