But he did that in order to do them good. God's purposes for His people were always for their best interest. We are also tempted to argue with God and rebel against him, especially when things are not going our way. When life is too complicated, or when it seems to be falling apart around us, or when we can't have the things we want, or we lose the things we have. If you're going through hard times, instead of hardening your heart against God, remember that he brings these things in the end to do us good, if we choose to continue in belief and not in unbelief.
Sin is serious.
Sin is blatant mutiny against God, and either sin or God's rule must die in my life. There is nothing more fundamental than that. Our sin was what sent Jesus Christ to the cross to die. And he did that so that we would stop sinning and turn to God in faith. God has prepared a Rest for us.