Why is it wrong to do bad things?
Here's the answer:
Doing bad things displeases God.
God is holy. His perfect goodness is far above us. Being bad is wrong because we're disobeying and dishonoring God. God created us to honor Him and do right things, so being bad displeases Him. He knows what's best for us, and doing bad things causes problems and makes us dirty inside.
We all need God to clean our hearts, forgiving us and giving us the desire to love and please Him. God's way to do this is through His own Son Jesus!
"All of us have become like someone who is 'unclean.' All of the good things we do are like polluted rags to you. All of us are like leaves that have dried up. Our sins sweep us away like the wind" (Isaiah 64:6).
"Everyone has sinned. No one measures up to God's glory. The free gift of God's grace makes all of us right with him. Christ Jesus paid the price to set us free" (Romans 3:23-24).
"God's grace has saved you because of your faith in Christ. Your salvation doesn't come from anything you do. It is God's gift. It is not based on anything you have done. No one can brag about earning it. God made us. He created us to belong to Christ Jesus. Now we can do good things. Long ago God prepared them for us to do" (Ephesians 2:8-10).