Many people can do great things, but without love. A person can give things to others, do things for others, even make many sacrifices, but not out of love. The desire for praise, acknowledgment, self-fulfillment, and more can motivate people to do such things, besides love.
In 1 Cor 13, Paul highlights that out of all the gifts that God gives us, love is the most important. This love is a godly love, one that is inspired by God and filled in us by God. All other things, even other gifts from God, will eventually pass away, but love will always remain.
In the church, we have love when we desire to build up one another. It is these relationships, built in Christ, that will last into eternity. In the same way that He has loved us, God desires that we love one another, strengthening and building up one another on this narrow path.
Summary by Meng Ping