Our “old man” is our old sinful nature that we have “crucified” by our repenting of our sins. We then buried our old sinful nature when we were baptized in Jesus name.

We put on the “new man” when we come up out of the water in Jesus name, and when we are filled with the Spirit of Jesus, which is the Holy Ghost. (Romans 6:4, Acts 2:38).

"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." - Romans 6:6

"But now ye also put off all these; anger, wrath [rage], malice [malicious behavior], blasphemy [slander], filthy communication out of your mouth [dirty language]. Lie not one to another, seeing that ye have put off the old man with his deeds; and have put on the new man, which is renewed in knowledge after the image of him that created him [as you learn to know your Creator and become like him]:" - Colossians 3:8-10

"That ye put off concerning the former conversation [conduct] the old man, which is corrupt according to the deceitful [deceiving] lusts; and be renewed in the spirit of your mind [instead, let the Spirit renew your thoughts and attitudes]; and that ye put on the new man, which after God is created in righteousness and true holiness." - Ephesians 4:22-24