Is it a sin to be rich?
No. But our attitude toward money and how we use it is the critical issue. When God blesses us with wealth and we use it responsibly we can do much to advance His kingdom. We can use money to reach others in ways we could not on a tight budget. Scripture tells us is much harder for the unsaved rich to trust in Jesus Christ than the poor (Matthew 19.23-24). Seeking after riches is a leading factor in Christians not producing fruit (Matthew 13.22) and spiritual ruin (1 Timothy 6.9). The love of money is also the root of all kinds of evil (1 Timothy 6.10).
When God blesses a Christian with riches he or she should use it to help the poor brethren in the church (Leviticus 25.35; Deuteronomy 15.7; James 2.15-17; John 3.17-18), widows and orphans (James 1.27), and the poor in his community (Proverbs 19.17; Matthew 19.21; Luke 6.38). The rich are not to spend their money lavishly on themselves without giving the bulk of their wealth to the church and the poor.
Instead of seeking after the riches of this sin-corrupted world, Christians should seek after spiritual riches – knowledge, understanding and wisdom. These three are more valuable than all of the riches in the world. There is only one place to find them – the Holy Scriptures. Instead of scheming how to become rich we should be reading, studying, memorizing and meditating on Scripture as much as possible.