Pastor Rick Warren of Saddleback Church says selfishness destroys relationships while selflessness builds them up.
He writes on his website that selfishness is actually the number one cause of conflict, arguments, divorce and war. If Christians are not careful in guarding their hearts from it, selfishness can easily creep into their relationships and destroy them.
"When you start a relationship, you work really hard at being unselfish. But as time goes on, selfishness begins to creep in," he says, noting that "we tend to put more energy into starting and building relationships than we do in maintaining them."
To fight this, Warren suggests that Christians exercise selflessness. He describes selflessness as thinking less of "me" and more of "you."
"It means thinking of others before you think of yourself and putting the other person's needs before your own," he says. "Selflessness brings out the best in others. It builds trust in relationships. In fact, if you start acting selfless in a relationship, it forces the other person to change, because you're not the same person any more, and they have to relate to you in different way."
Warren himself has seen this unfold many times. Even the most unlovable people that nobody wants to hang out with miraculously transform whenever someone shows them some kindness and gives them what they need instead of what they want.
"This is the biblical principle of sowing and reaping. What you sow, you're going to reap," he explains. "God rewards selflessness with eternal life. He has wired the universe so that the more unselfish you are, the more he blesses you."
Warren says God does this because He wants His children to become unselfish like Him. Everything people have in their lives is a gift from God because He has been unselfish with them, he says.
Galatians 6:7-8 supports Warren's statements: "The person who plants selfishness, ignoring the needs of others — ignoring God! — harvests a crop of weeds. All he'll have to show for his life is weeds! But the one who plants in response to God, letting God's Spirit do the growth work in him, harvests a crop of real life, eternal life."