1 Corinthians 13:4-7 (NIV)
4 Love is patient, love is kind. It does not envy, it does not boast, it is not proud. 5 It does not dishonor others, it is not self-seeking, it is not easily angered, it keeps no record of wrongs. 6 Love does not delight in evil but rejoices with the truth. 7 It always protects, always trusts, always hopes, always perseveres.
This is one of the main verses Christians refer to when talking about love. I think this verse is helpful in showing the practical forms love takes but does not define what love is. Now I know that the English word for love is not as descriptive as the Greek are but those definitions deal with how we love (agape - unconditional) or who we love (filio - brotherly love). I want a non-abstract definition of what love is, not how, who, or why, according to the Bible. I imagine that it should take a look at many verses since I don't know of just one that lays it out, but I would be glad to be shown wrong.