Worship
Romans 12 starts with
1 I beseech you therefore, brethren, by the mercies of God, that you present your bodies a living sacrifice, holy, acceptable to God, [which is] your reasonable service. 2 And do not be conformed to this world, but be transformed by the renewing of your mind, that you may prove what [is] that good and acceptable and perfect will of God. [NKJV]
Many translations translate "reasonable service" as being an act of Worship. This line basically stays that our physical lives need to be in service and worship of God not only this, it is the only logical and reasonable thing to do. Logical because what else does one do when considering God and reasonable because we wishes us to be in intermate relationship with Him. The more involved we are with God, the closer we are to Him and the less likely we are to stumble and even fall away.
So how far back doe intentional Worship of our God go? Right back to the beginning; Genesis 4:1-4.