God set before us His blessing and curses (Deuteronomy 11:26). When we choose to obey, there’s a blessing. When we choose to disobey His good law, there’s a curse. The curse brings trouble and no peace. Therefore, we know we are off the track and that brings us back for His forgiveness and salvation.
Without justice and righteousness, the humane mercy ignores the problems which in the long run become spoiled and harmful like cancer to the body. Only God can balance love and justice perfectly because He is infinite and all-knowing.
God promises that when we humble ourselves, His wisdom will flow to the people who revere Him, like the water flows from high to low.