"For the word of the cross is folly to those who are perishing, but to us who are being saved it is the power of God." (1 Corinthians 1.18)
"For the word of the cross..." Inevitably, the more time we spend in the scriptures, the more we see the importance of reading them in context. Starting with "for," Paul forces us to read back at least one verse, where he has referred to preaching the gospel, "not with words of eloquent wisdom," but truthfully. In Corinth (and other large Greco-Roman cities) well-skilled orators and philosophers would gather to speak, debate, and ultimately, try to make a name for themselves by displaying their "wisdom." Verse 18 (and through verse 5 of chapter 2) is meant to remind the Corinthians of the power of the message of the cross. In other words, Paul says that no matter how eloquently or skillfully put, the crucifixion of the Messiah cannot be explained in a way that will make sense. Because we cannot reason our way to an understanding of God, Paul calls the Gospel "folly" or "foolishness" to the darkened mind. Paul means for the Corinthians (and us) to understand that the cross, more specifically, is impossible to understand by means of human wisdom, reason, or rationality. In fact, the crucifix was such a horrendous means of execution that it was taboo to even talk about in polite company.
"For the word of the cross is folly to those who are perishing..." Who are those who are perishing? Two groups of people make up those who are perishing: 1. Jews and 2. Greeks (Gentiles) - and that pretty well includes everyone who does not embrace the gospel with his/her whole life! To the Jews, the cross is folly for a couple of reasons. The Jewish people were looking for signs (1 Cor. 1.22), and though Jesus did His share of miraculous signs, they were not the signs any Jew was expecting. He did things like wash His disciples' feet (John 13.1-20) and drink from a cup borrowed from a Samaritan whore (John 4.1-30). But the Jews wanted a political leader to rise up to restore Jerusalem to its former glory, free from Roman rule. They looked for displays of raw power, not displays of love. Plus, they knew their Torah; they knew that "a hanged man is cursed by God" (Deuteronomy 21.23). And even though they had the prophets and knew Isaiah 53, a Messiah who suffered (or served) was way outside the expectations. The cross (and its implications) was simply impossible for Jews to overcome.
To the Greeks (Gentiles), the cross is folly for entirely different reasons. They valued men like Plato and Aristotle. The Greeks sought wisdom (1 Cor. 1.22), and though Jesus was incredibly wise (ritually stumping the Pharisees and teachers with His answers when they challenged Him) the Greeks dismissed and ridiculed the gospel and those who preached it due to the simplicity of the message and the typical blunt-ness with which it was presented. Paul's lack of "words of eloquent wisdom" (1 Cor. 1.17) seemed uncultured and laughable. Plus, they had their preconceived ideas of God - God could not become a man, because that would involve Him in mundane human affairs, which was insulting for a god. Then theres "apatheia," or the inability to feel. To the Greek, Jesus could not be God because if He felt sorrow or joy, then some person must be influencing Him and is therefore more powerful than God. So for the Greek who tried to philosophize his way to God through mere human wisdom and rhetoric, the cross was not only an impossibility, but was ridiculous.
"For the word of the cross is folly to those who are perishing, but to those of us..." To those who can come to the cross in spite of our expectations. To those who come without needing wisdom or reason.
"For the word of the cross is folly to those who are perishing, but to those of us who are being saved..." Who treasure Jesus. Who have been justified and redeemed. Who are being sanctified. Who will one day be glorified.
"For the word of the cross is folly to those who are perishing, but to those of us who are being saved it is the power of God." The cross. The gospel. The joyful (Heb. 12.2), sorrowful (Matt. 26.38-39), beautiful, painful torture and death by the most excruciating and disgusting means of punishment ever invented. Then the defeat of death and its sting (1 Cor. 15.55-57). Salvation (Rom. 1.16). Eternal life (1 John 5.20).