"Truly, truly, I say to you, an hour is coming, and is now here, when the dead will hear the voice of the Son of God, and those who hear will live. For as the Father has life in himself, so he has granted the Son also to have life in himself." (Jesus' words from John chapter 5)
"And this is the will of him who sent me, that I should lose nothing of all that he has given me, but raise it up on the last day. For this is the will of my Father, that everyone who looks on the Son and believes in him should have eternal life, and I will raise him up on the last day." (Jesus' words from John chapter 6)
What is the purpose of love? What is love intended to do? A typical Christian response might be to say that the purpose of love is to "serve another." There is some truth to that, but that doesn't really answer the question. That tells us what love does, but it doesn't tell us what love is intended to do.
Love purposes to make alive. It purposes to call out and raise up the other person, to raise them up to life. Jesus knows this, and in the end His love will be effectual for all those who are His. He will literally call them out of death and raise them up. That is the purpose of love. That is what it is ultimately designed to do.
We were created as communal, relational creatures. Once God created Adam, the first thing he said was "It is not good for man to be alone." He made us to live in relationships where we each call to one another and raise each other up with our love, just as He does with us.
This is why saying that love is to "serve" is insufficient. When you serve someone and it falls on deaf ears, it hurts. But why does it hurt, then? Are you being selfish? Are you attaching too many strings? In some cases, perhaps. But in the bigger picture of things, it hurts because you know that love is intended to make alive, and if the other person is deaf to it, that hurts. You're love has fallen to the earth, and they have not turned their face toward you.
And yet these are the sufferings of God, the sufferings of Christ in this world. When we know this kind of pain, we know a glimpse of His. His sufferings are not a general, "Oh, look at how unhappy I am with what little Jimmy said to his mother." His sufferings are ultimately about disappointed love. The suffering of Christ in this world is literally about loving and forgiving the world and having the the world be indifferent toward His love, shun Him, and/or ultimately seek His death.
This is the incredible beauty and the potential tragedy of love. Love is to make alive.