...”How does one demonstrate they ‘rely and are in Jesus Christ’? ...Not to all the people, but to the Heavenly Father?”....
Why would you see a need to “demonstrate” you are in Christ to the Heavenly Father when He IS God...when he clearly states...”I know the ones I have chosen”...and ...”My sheep hear My voice, and ‘I know them’, and they follow Me”... But if any man love God, the same is known of him.
John 13:18....John 10:27...John 10:4,8,16..ICor.8:3
"...you do not believe because you are not my sheep."
The reason they do not believe is BECAUSE they are not His sheep.
Ah, the 'chosen'. (Eph. 1:4) Paul says the chosen (elect) were chosen 'before the foundation of the world'. (This is the Greek word katabole, which means casting down - overthrow) Genesis 1:2. Meaning, they are the ones, like Paul, justified... And yet Paul showed what his passion was before he took that trip to Damascus. Now, what was Saul's/Paul's problem. Well, one only need to read Stephen's sermon in the book of Acts, to see what those of the religious order were against.
Stephen did give a really decent sermon on Christianity and its early beginnings all the way back in the 'Old Testament'.