When you made Jesus Christ the Lord of your life and were born again, you were washed in His covenant blood, shed for you, and were made His righteousness (2 Corinthians 5:21)–no longer a slave of sin. You were not born a servant of the Most High, but a son (Galatians 4:7). You become a servant of God, like your blood Brother, Jesus, by choice (Philippians 2:7). Since you are a son and a joint heir of God through Him, then “let this [same] mind be in you, which was also in Christ Jesus: who, being in the form of God, thought it not robbery to be equal with God” (Philippians 2:5-6, KJV). Jesus did not consider He was robbing His Father of honor, sovereignty, or deity to be equal with Him. Let that same mind be in you. He made you His righteousness and made you to sit together with Him in heavenly places (Ephesians 2:6). Then you should not consider yourself robbing Jesus to be called His joint heir. You didn’t do that for yourself. God did it for you, sacrificing His Son, Jesus, “the last Adam” (1 Corinthians 15:45), so you could be restored to the sonship and fellowship with Him that was lost by the first Adam.