“Come close to God, and God will come close to you. Wash your hands, you sinners; purify your hearts, for your loyalty is divided between God and the world. Let there be tears for what you have done. Let there be sorrow and deep grief. Let there be sadness instead of laughter, and gloom instead of joy. Humble yourselves before the Lord, and he will lift you up in honor.” James 4:8-10 (NLT)
God loves us and desires closeness with us, but instead of demanding it, He invites us. Love is always invitational and not forceful, and because God is love, He invites. Through James, God is letting us know that we are in need of cleansing if we are to experience closeness with Him. Like a parent bathing a toddler, our heavenly Father wants to cleanse the dirtiness of this world from our lives. He lets us know that our divided hearts have caused us to follow our own plans instead of His and caused us to compromise living Holy for Him. We have become dirty by living according to a dirty world.
When we truly love God, we will be sad over our sin because we have not just broken a rule (impersonal), but have broken a heart (relationship). People who are not in a relationship with God laugh at sin, but those who have experienced His forgiveness and love can no longer laugh, but mourn. They mourn because they see the damage sin causes in the lives of those Jesus came to rescue from its power.
If this applies to you, then rejoice when you mourn over your sin, because it means you are His child, and that he has cleansed and forgiven you from all your sins. Rejoice, because you no longer desire to live for the things of this world, but for Jesus! Since God is now your Lord and Leader, continue to humble yourself, putting His will and plans for your life before your own. When you do this, He will use you (lift you up) to be light and salt in a dark and tasteless world. People will see Jesus in you and through you as you daily draw close to and walk with Him.
If you still laugh at sin, turn from that kind of life and cry that you are still lost and in need of forgiveness. Turn to Jesus and ask Him to save you. After you have experienced His forgiveness and grace, your mourning will turn to laughter and celebration.