To live in the light means to be obedient to God by allowing His Spirit to lead us into all truth. Does this mean that we never sin? No, if it were possible for us to live sinless lives, then Jesus died in vain. It means that we do not choose a lifestyle that constantly repeats the same sins. All humans fall to temptation, but we should not allow the devil to use those failures to beat us up and keep us depressed. Do our failures send us to hell? No, but they do break our relationship with Jesus Christ. So what do we do? John tells us in verse 9, when we fail and we will, then we must confess our sins and allow God to cleanse us from our sins. Then our relationship is restored and we can rejoice in His goodness and mercy.