Matthew 5:43-48
"You have heard that it was said, 'You shall love your neighbour and hate your enemy'. But I say to you, love your enemies, bless those who curse you, do good to those who hate you, and pray for those who spitefully use you and persecute you, that you may be sons of your Father in heaven; for He makes His sun rise on the evil and on the good, and sends rain on the just and on the unjust.
For if you love those who love you, what reward have you? Do not even the tax collectors do the same? And if you greet your brethren only, what do you do more than others? Do not even the tax collectors do so?
Therefore you shall be perfect, just as your Father in heaven is perfect."
This may look easy to do for a lot of people when life feels easy and one has a lot of support around, as when life becomes difficult and the support around you becomes scarce this will become more difficult. It is during times of trials that you are the most tested with this part, as when life feels easy on you, then loving others just feels easier. Makes sense?
When you become a target of the enemy, this is when you become more tested in this part. How many are capable of loving people who have become their enemy? Jesus Christ managed this, even though He was perfect in all His ways! He loved them even whilst He was suffering and dying on the cross. We are meant to keep on learning from Him, yet, when it becomes difficult, it isn't always easy doing this. Only when we get more love refill from God, as you have stated too. By ourselves it isn't natural for us loving those who harm us, but through Christ's love we can manage this!
2 Corinthians 5:14a
"For the love of Christ compels us"
Keep on standing strong in Christ's love!