There is nothing that will ever humble a man or a nation but the cross of Christ. The cross tells us the simple, plain truth about ourselves.
Think of it like this. Why did the Son of God ever come into this world? Why did He leave the courts of glory? Why was He born as a little babe? Why did He take unto Him human nature? There is only one answer. He came because man could not save himself. He said that. “The Son of man,” he says, “is come to seek and to save that which was lost” (Luke 19:10). And when I look at the cross and see Him dying there, what He tells me is this: You have nothing whereof to boast. The cross tells me that I am a complete failure, and that I am such a failure that He had to come from heaven not merely to teach and preach in this world, but to die on that cross. Nothing else could save us.
– Martyn Lloyd-Jones and Robert Backhouse, Walking with God Day by Day: 365 Daily Devotional Selections, (Wheaton, IL: Crossway, 2013).