https://www.mljtrust.org/sermons-online/numbers-11-4-6/the-mind-of-man/

How has sin affected humanity and their reasoning? Many scorn the ideas of God, Jesus, and the need for salvation and say that no rational person can possibly be a Christian. In this sermon on Numbers 11:4–6 titled “The Mind of Man,” Dr. Martyn Lloyd-Jones shows that Scripture has a very different idea of what it means to be reasonable. After the people of Israel are set free from bondage in Egypt, they quickly begin complaining that they do not have the food and comfort that they had while they were slaves. This is wholly irrational, but it serves to show that humans are fallen, and sin has affected minds and hearts. It is rational to believe that God has sent Jesus into the world and died, but people are blinded to this truth until God graciously opens the eyes to see Him and believe Him. Humanity’s essential problem is that they are fallen and blinded by sin and immorality. Fallen people are slaves to sin until Jesus Christ overcomes the sinful heart and makes them new.