Love is patient, love is kind.
Thus begins one of the most popular passages of the Bible. It's always been interesting to me that it's almost always taken out of context; it sits right in the middle of a lesson on spiritual gifts, extolling the importance of practicing these gifts out of love for one's fellow man. It's agape love, not eros love, which is why the KJV chose the word "charity" instead. But "charity" is too weak a word to modern tongues. What Paul is speaking of is Christian love in the most complete sense.
It does not envy, it does not boast, it is not proud.
"Spiritual gifts" take a lot of flak from the secular community. Usually people think of speaking in tongues, faith healing, and predictive prophesy (which are in fact all included by Paul), but the term is far more general than that. It also encloses gifts of teaching, outreach, management, and the more mundane forms of healing and multilingualism. The early Corinthian church was clearly keen on promoting all of these spiritual gifts, but they were losing sight of how they were to be used. 1 Corinthians 12 tells us that the "greater gifts" were being sought to the exclusion of the lesser ones. What Paul is saying in this chapter is that not only is it bad to downplay the lesser gifts, but to do so misses the entire point of their being spiritual.
It is not rude, it is not self-seeking, it is not easily angered, it keeps no record of wrongs.
All spiritual gifts -- and indeed, all works done in the name of Jesus Christ -- need to be practiced in the spirit of agape, truely selfless love. Everyone can conjure up a mental image of some street corner preacher shouting their idea of the Gospel to everyone in range, threatening them with the flames of Hell unless they come around to their own way of thinking. But few will think of the time they gave a coin to a homeless person while silently calling them a lazy mooch, or when they gave a minute of their special talents to another just to show off how competent they were.
Love does not delight in evil but rejoices with the truth.
Everybody knows what evil is, right? Murder, enslavement, exploitation, manipulation, et cetera, et cetera. But where the Bible is concerned, evil is anything not in line with God's own commands, either in the letter or in the intent. "An' harm ye none" just isn't good enough, because "harm" can be subtle and invisible, working its damage slowly over months and years. A knowing lie, a selfish motive -- anything that is intended to serve me rather than you -- can pollute a good deed, no matter how "spiritual" or "loving" it looks to outsiders. Perhaps it only pollutes my own heart, but damage is done nevertheless.
It always protects, always trusts, always hopes, always perseveres.
-- 1 Cor. 13:4-7, NIV
"Protect" and "trust" -- two action verbs that are entirely focused on their object. "Hope" and "persevere" -- two more that are entirely focused on the future. All four involve the unknown, and as we all know, it is human nature to fear the unknown. And that's where the sacrifice comes in. Agape love asks us to forget ourselves completely and place ourselves entirely in the service of another, in everything from completing the job we were assigned to spoiling our SO on our anniversary to fighting and dying for our country.
It's not easy. But then, if it was, Christian churches wouldn't need to get letters about it from their founder, would they?