Actually, you do, by all you've explained and posted. You've claimed that one must continue to believe in order to be saved.
Yet, Jesus said clearly that those who believe HAVE (as in POSSESS) eternal life.
John 3:15,16, 36, 5:24, 6:47.
Then in 10:28 Jesus gave us the CAUSE and EFFECT of having eternal life:
He is the CAUSE of having eternal life by His statement, "I give them eternal life".
Never perishing is the EFFECT of having eternal life by His statement, "and they shall never perish."
So your claim that one must continue to believe is false.
If it was true, Jesus WOULD HAVE HAD TO SAY this:
"I give them eternal life, and IF THEY CONTINUE TO BELIEVE, they shall never perish."
But we all know He never said that. In fact, between being given eternal life, and never perishing are NO CONDITIONS placed on recipients. Maybe you hadn't considered that.
Except there are no verses that say this. And the sealing refers to the indwelling of the Holy Spirit. The influence of the Spirit only occurs when the believer is filled with the Spirit (Eph 5:18, a command) and walking by means of the Spirit (Gal 5:16), in order to not fulfill the lusts of the flesh.
When the believer is grieving (Eph 4:30) or quenching (1 Thess 5:19) the Spirit, does that sound like being influenced by the Spirit.
I should say not.
Well, I do agree with you here. Your view is only a hypothesis. It's sure not fact, or what Jesus said in John 10:28 would be FALSE.
Are you prepared to state that what Jesus said in that verse is FALSE?
Well, you've got another verse that makes a statement of Jesus to be FALSE!!
Luke 8:13 - Those on the rocky ground are the ones who receive the word with joy when they hear it, but they have no root. They believe for a while, but in the time of testing they fall away.
Please don't bother trying to explain this away by some mumbo jumbo about this not being actual saving faith. It's the SAME WORD used for others who have believed for salvation.