The writer to the Hebrews writes in chapter 10 verse 10 that Jesus Christ was offered bodily once for all. But why was Jesus an Offering? The answer is found in the text itself, Jesus was offered so that all can be sanctified. To be sanctified is to be set apart. To be set apart is to be renewed in our minds and refreshed in our heart to have allegiance unto none other than Jesus Christ. In other words, to be set apart is to offer ourselves (our bodies) as a living sacrifice.

Jesus offered Himself to the death sacrifice so that we can offer ourselves as a living sacrifice.
Jesus Christ offered his body and we are expected to do the same as well.

In other words, an offering for an offering. His offering warrants ours.

Hebrews 10:10 (KJV)
10 By the which will we are sanctified through the offering of the body of Jesus Christ once for all.

Romans 12:1-2 (KJV)
1
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.
2
And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God.