The cross dealt with the old man to kill the natural life with its natural ability (2 Cor. 4:10a, 11a, 12a, 16a). A person who is very capable may do many things by his natural ability, but that ability should be broken. The apostle Peter had his natural strength and ability, and he thought he was stronger than the other disciples. He told the Lord Jesus that even if all the others were stumbled, he would never be stumbled (Matt. 26:33). Then the Lord said, "Before a rooster crows, you will deny Me three times" (v. 34). The Lord allowed Peter to fail utterly in denying the Lord to His face three times (John 18:17, 25, 27), so that his natural strength and self-confidence could be dealt with. Then after the Lord's resurrection, He came back and asked Peter three times if he loved Him (21:15-17). The intention to love the Lord is right, but to love the Lord by our strength and by our ability is wrong. That is natural, and anything natural must be crucified.
Second Corinthians 4 shows us that to the apostle Paul the Lord's death became a constant killing. We may use today's medicine as an illustration of how we can experience this killing. In an antibiotic there is the killing element to kill the germs. Today the all-inclusive Spirit is our divine antibiotic. In the all-inclusive Spirit, there is the killing element of Christ's death. Paul said in 2 Corinthians 4 that he was under the killing of the death of Christ all the time. This death kills our flesh and our natural man.
In verse 16, Paul said that his outer man was decaying, being consumed, being wasted away, or being worn out. Our outer man is being consumed. Before a brother gets married, he may not be consumed that much. Many times the most consuming element to a brother is his wife and then his children. The wife is a big "cross," and the children are small "crosses" to him. To be crossed out is to be consumed. The parents need to be crossed out, consumed, by their children. The killing of Christ is a consuming.
Brother Watchman Nee referred to this consuming as the breaking of the outer man in his book entitled The Release of the Spirit. If the outer man is not broken, the inner spirit cannot be released. At the end of his ministry, Brother Nee always talked about the breaking of the outer man, which is the killing of the death of Christ.
Galatians 5:24 says that they who are of Christ Jesus "have crucified the flesh with its passions and its lusts." The flesh with its passions and its lusts has been crucified on the cross.