In light of the gospel, in light of how we are to live sacrificially for God, in light of using our spiritual gifts... we must have love for one another. In this passage, Paul defines the nature of love, as well as 9 ways in which the Christian can practice and live out love towards one another.
The nature of love (v9)
Love is genuine
Love hates evil
Love holds on to good
The practice of love (v10-13)
Show brotherly love toward one another
Show honor to others over self
Don't be lazy in what you ought to be doing
Overflow a godly spirit
Serve the Lord
Rejoice in hope
Be patient in trials
Be constant in prayer
Give to the needs of other believers