knowing that God loves people and relationships...and knowing that satan hates what God loves... it helps to put this verse in perspective..
"For we wrestle not with flesh and blood , but against principalities, rulers of darkness and spiritual wickedness in the heavenly places.. "
so remembering that 1/3 of the demonic "angels" are here on earth and they are spirits who need a host body to do any such damage to people then we can see that even though we may think that it is "our relative" or "a person" for that matter, it really is the spirit that is ruling their mind set whispering into their ear acting like it is the hosts thought....the demon being hosted offering to enter through a host (person) to do negative harm and damage through that person so that they can impart their (the demons) emotion or the demon's disease on that person .
Jesus commanded the sickness to come out of the people. we are to take His authority and walk likewise in it.
Remember Peter when he offered up something to Jesus and Jesus retorted, "get thee behind me satan." Pow! Jesus knew that that was not Peter's suggestion.
People who are not aware of living in the Kingdom mentality( Heaven on earth) will do and say flippant things. We have all forgotten who we were when we did not have on our armor nor remember that we have an enemy or that we are in a battle...
The enemy is satan and his demons who desire to be used through another person.
Remember the demon called Legion? Jesus was getting ready to cast them into outer darkness or the dry places and they said..."Cast us into the herd of pigs!" So he did but the pigs ran over the cliff and then who knows where the spirits went after that..
So to forgive a person... and this is important because the word says that our father in heaven won't forgive us if we do not forgive the one who hurt us.. We are not wrestling with our Mother in law or our brother or our spouse it really is a spiritual battle. Most people I know want to do good and love not purposely hate.. any spirit of jealousy, revenge etc. is from the devil and his demons. people are just convinced that that is them.. when we walk in the flesh we will fulfill the lusts of the flesh. we need to renew our thinking with God's word and obey.
another thing is that we do remember sins that were done against us. we've all had people give us a hard time and we too may have done things to others.. we just did not know what we were doing..."Father forgive them for they know not what they do".. and if we can remember that it really isn't that person but a ruling spirit or stronghold on that person's mind that it is actually them instead of revealing a demon (that is unseen and no one really teaches this much) then it will help us to know that that person is actually being a puppet and is a victim of the devil.