Frustration

Do you ever do something and then totally kick yourself afterward? I know I do that often, but today I really did it. I realized today how far I still have to go in my walk with Christ, as well as fostering charity and love towards others. I am trying to not let this depress me, but it is hard. I really feel like a jerk and hope that this person forgives me, but that is their choice. Why though, as humans, do we do something we know is wrong or not right in sight of God? No matter what it is. Murder, lying, stealing, gossip etc...You get the drift. This is a very perplexing question when you are trying so hard to walk the straight and narrow and screw up. Don't you agree?