At the very least, the holiness of God means He alone is God and His actions are determined according to His own will alone.
At the very least, His righteousness means that His Word and judgment are perfect.
Our sin is dreadfully evil, so powerful that it will not respond to either His kindness nor His warnings of judgment, as Isaiah 26:10-11 says,
Your kindness to the wicked does not make them do good. Although others do right, the wicked keep doing wrong and take no notice of the LORD’s majesty. O LORD, they pay no attention to your upraised fist.
It is only through being born again that we become new, our rebellion is ended, our sins are forgiven, and we are delivered from the wrath of God to come.