The New Testament basically defines our service to God as instruments for Him to use as He wishes to help bring His creation of humans back to Him. As humans, we have a hard time being His instruments. We want to be in control of this current life on earth and to decide who and what we are. We have a hard time understanding a verse like 2nd Corinthians 5:17 that lets us know that we are a new creation after we have received His salvation.