One of the most important truths we can know and apply to our lives:

Secrets of Heaven 6206: It should be recognized that all evil flows in from hell and all good from the Lord by way of heaven.

Heaven and Hell 302: If we believed, as is really true, that all good is from the Lord and all evil from hell, we would not make the good in us a matter of merit nor would evil be imputed to us.  Instead we would look to the Lord in all the good we think and do, and all the evil that inflows would be cast down back to hell where it came from. But because we do not believe that there is any influx into us either from heaven or from hell, and so suppose that all the things that we think and will originate in ourselves, we appropriate the evil to ourselves, and the inflowing good we we mess up with merit by taking credit for it.