The Hearing Ear

The Ephesians had "learned Christ" in the only way in which He can be learned. The natural man may learn of Christ; the spiritual man alone can learn Him. For "the natural man receiveth not the things of the Spirit of God: for they are foolishness unto him: neither can he know them, because they are spiritually discerned." 1 Cor. 2:14. There must be the hearing ear before Christ's words can be understood. As Jesus said to the Pharisees, "Why do ye not understand My speech? even because ye cannot hear My word." John 8:43. The Ephesians had heard Christ, and been instructed in Him. The words that He spoke, "They are spirit, and they are life," and they had produced their quickening power on the hearts of these saints. Hence they knew the truth as it showed itself in the spotless, holy life of Jesus.
This was to be practically manifested in their own lives. They belonged no more to the flesh, and therefore their walk was not to be according to the old model-"the old man, which is corrupt according to the deceitful lusts." They were finished with the old creation as to their standing before God, and were seen in a new creation as quickened together with Christ. This then was to be their new model. Being "renewed" in the spirit of their mind, they were to walk after a new fashion, not according to the law of the old nature, but as having "put on the new man, which after God is created in righteousness and true holiness [holiness of truth].”
The new man is man in the new creation-the creation which has its head in Christ, the creation which draws its character from Christ. To walk as having put on the new man is therefore to walk as Christ walked, for this new man is created according to God's nature in righteousness and holiness suited to His own truth.