Let us pause for a moment and think about the scripture below.
Knowing this, that our old man is crucified with him, that the body of sin might be destroyed, that henceforth we should not serve sin. For he that is dead is freed from sin. - Rom 6:6
Here is a good question to answer. What is the old man? Well, to find the answer, we can use two approaches! The first is to check elsewhere in the Bible for the interpretation. Let’s do this now by starting at the beginning based on the Book of Genesis.
And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life; and man became a living soul. – Gen 2:7
The man that the scripture formed out of the dust, was the human body! Therefore, we know the term ‘man’ here refers to the human body!
For the second approach, we can find out the interpretation by examining the context in which the concept is used.
…our old man is crucified with him, that the body of sin might be destroyed
Old Man = Body of sin.
The ‘man’ is called old here to cause the Church to see clearly, that their bodies have indeed been made new at salvation. The word ‘old’ here means previous. The previous man was sinful in makeup. Yes, before we received the Holy Ghost, our bodies were bodies of sin! We were found smack dab in Romans 7! Evil concupiscence ruled in our flesh! However, God gave us the gift of Jesus Christ – He gave us the new man!
That ye put off concerning the former conversation the old man, which is corrupt according to the deceitful lusts; And be renewed in the spirit of your mind; And that ye put on the new man, which after God is created in righteousness and true holiness. Eph 4:22-24
The scripture says we have put off the body of sin, and have put on the new man – a body of righteousness. This causes us to know that once we are saved, our bodies are not sinful and evil as many believe. In fact, when you were receiving the Holy Ghost, God spiritually circumcised all the sinful nature out of the flesh! After doing so, He entered into it, and started a law, called the law of Spirit of life, which is a law of righteousness.
The flesh of every son of God is therefore holy! This then I say to you.
I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.