Love is tied to justice because if you love someone you can not be unjust to them, and love is tied to everyone and the love you feel for one person is the love you feel for all.
I would define love as care for other humans and their wellbeing, no matter their background, thoughts, actions, and religion, because God loves them as much as he loves us, and we should follow that by helping to care for them.
We can only love others when we live for and with others, as well as for God. We must also believe that social justice is one of the basic principles of love.