But one reason I didn’t mention is that sometimes we lack peace because we knowingly sin against God.  You can see this example in Genesis 4 when Cain offered a sacrifice that God did not receive.  He instantly lacked peace.  As Christians, this happens to us, as well.  Conviction of sin can cause anxiety when we don’t repent.  This is a kindness of God.  It’s a way that He shows us that there’s a better way to live.