So the one who boasts must boast in the Lord. For it is not the one commending himself who is approved, but the one the Lord commends.
Our only real value is found in Christ. God Himself imputes value to us through His creation of us and His recreation of us through the Blood of Jesus. He has not only created us with inherent value He has redeemed us and validated our value which is found only in Christ. Thus, there is nothing about which we can accurately boast except in Him since all we were and all we are is found only in Christ. All things were created through Him and He alone is able to redeem that creation. In Him all things hold together and, by inference, outside of Him all things fall apart. Thus, He has created and recreated and all of the blessing and glory is His. This frees us up to be His people living as He calls for His glory. It is for freedom we have been set free.