Love one another earnestly from a pure heart because your regeneration was called into existence by the imperishable Word of God.
1 Peter 1:22–25 (ESV)
22 Having purified your souls by your obedience to the truth for a sincere brotherly love, love one another earnestly from a pure heart, 23 since you have been born again, not of perishable seed but of imperishable, through the living and abiding word of God; 24 for “All flesh is like grass and all its glory like the flower of grass. The grass withers, and the flower falls, 25 but the word of the Lord remains forever.” And this word is the good news that was preached to you.
Do you see the connection? The imperative is to love one another earnestly from a pure heart. The reason given? Because the very Word of God which impregnated your rebirth, your regeneration, is imperishable, living, abiding, staying. Our love for one another as Christians will be characterized by the same imperishable, living, abiding, staying nature in pure, unmasked sincerity. Our love for one another in the church–not merely love for our brothers or our mother or our kids, but love for one another within our family called the church–is to reflect the tenacious, concrete of the promises of God, with no hint of falsehood, agenda-setting, or self-absorption. Peter calls this the distinguishing mark of Christian love–that it never dies and it is never polluted because it has been birthed by an undying Word.
Everything else withers, everything else rusts, everything else falls apart or grows old like an overused laptop battery, an aging loaf of bread, or that worn out pair of jeans with the ever-expanding hole in the knees, but our love for one another is to remain just like the Word of the Lord remains.
What will it look like for me to love my Christian brother and my Christian sister earnestly with a pure heart? No agenda of my own, no manipulation, no self-pleasing, which connotes the abiding, tenacious, imperishable Word which called my faith into being? It certainly means I would never give up on someone. I would never walk away simply because my feelings were hurt or I felt that my rights or my preferences were being squelched. I would be thick-skinned and big-hearted. I would pursue your good for God’s glory, and grow amnesic towards my own aims and lusts for glory.
And certainly this call to love is not subjugated to a “Young Marrieds” class or a “Singles” ministry or a “Golden Years” group. It can’t be contained in a white church or a black church or a rich church or a poor church. Those terms are oxymoronic to the Christian faith (just take a look at what happened when Christian love exploded in Antioch). This love cuts across our attempts to isolate ourselves into homogenous predefined “Likes” where it is safe to love, and calls us out to love purely forever those entirely unlike us.
This love will be a love that survives inconvenience, personal preferences, my rights, and the false boundaries I construct in order to maintain a safe place for me to be alone and comfortable. The Christian life cannot be lived authentically in isolation. 
Church, may we love one another in such a fashion that the very definition of “love” will be reclaimed for Christ, and bystanders will say, “I’ve never seen anything like it in this world; their love must come from another place.”
 Karen H. Jobes, 1 Peter, Baker Exegetical Commentary on the New Testament, 123 (Grand Rapids, MI: Baker Academic, 2005).