If you are a church member, the janitor, or the pastor, it really doesn’t matter; if you or I have no integrity, we are grieving the Spirit and quenching His work in us, and it will stunt your spiritual growth.
Let’s say some Christian is hedging on his taxes (a fancy word for cheating). Would you want them to be the church treasurer?
What does this person do with Romans 13:7 where it commands believers to “Pay to all what is owed to them: taxes to whom taxes are owed, revenue to whom revenue is owed, respect to whom respect is owed, honor to whom honor is owed?”
A lack of integrity will stunt your spiritual growth, because you cannot read the Bible long before you are convicted by your lack of honesty, and that plagues you when you read the Bible (as it should), so you stop altogether and don’t even read it anymore, or at least very much.