The word radical comes from the latin word radix which means root. To be radical means to go for the root!
Further, to go for the root means to zero in on what really matters! So what’s the root? The root is that you and I are both filthy sinners. You’re no less than I am and I’m no more than you on this aspect. God on the other hand is way too beyond us in perfection and holiness. Way beyond.
Consider this picture: He is like a vast ocean, perfect in its peacefulness yet very deep in its depth. It’s beholding majesty holds life for thousands. We on one hand are like an uncontrollable raging river. There is no music in our sound or harmony in our ways. We are bedded by boulders and rocks and not too much life can stand our wildness. Yet have you ever seen a mouth of a river welcomed in by a vast ocean? The wildness of the river is tamed and peace is henceforth predicted. The river ultimately dumps itself in the ocean and the ocean willfully allows another gradient of salt from it. God in His love and mercy allowed us through Jesus to come before Him and rest in the depth of His grace. Jesus has opened the way for us out of the rage of the river and into the peace of the ocean. That will have to be the root. Understanding how Jesus radically made it possible by getting to and dealing with the root of all our problems which is sin will make us live a radical life for Him. It calls for us to go for the root be radical for God.
God shows his love for us in that while we were still sinners, Christ died for us.