We never think why Jesus was always seeking to connect our understanding to the connected themes of forgiveness and the abundant life, i.e. forgiveness leads to an abundant life; abundant living is contingent on forgiveness.
The fact is we cannot hope to experience His abundant life while we harbour bitterness of any sort or size in our heart.
There is a direct correlation between hatred of another person and hatred within our person.
If we have anything against anyone we bear fear that no human was designed to bear.