To me, clearly one of the most challenging things that Jesus said was:
“Do not think that I came to bring peace on earth. I did not come to bring peace but a sword. For I have come to ‘set a man against his father, a daughter against her mother, and a daughter-in-law against her mother-in-law’; and ‘a man’s enemies will be those of his own household.’ He who loves father or mother more than Me is not worthy of Me. And he who loves son or daughter more than Me is not worthy of Me. And he who does not take his cross and follow after Me is not worthy of Me. He who finds his life will lose it, and he who loses his life for My sake will find” (Matthew 10:34-39).
We see the fruits of this everyday. They are not willing to pay the price necessary to submit to God. Their flesh is still predominant.
The most chilling moment for me at the cross was when darkness fell upon the world. I am continually in awe at the depth of the Bible’s teachings on light and darkness. “The way of the wicked is like darkness; They do not know what makes them stumble” (Proverbs 4:19).
People walk in darkness and do not make sound decisions. It skews their perceptions of the world and they do not attribute the proper value to things. Hence, they cannot leave their overcome their own fleshly desires and come to Christ (James 4:10).