Your example doesn't work for me. My mom was not a Christian for most of her life. I always remember when I was a teen, she counted the money a bank teller had given her, and she was given too much money. She went back to the teller and gave her the extra money back.
When I asked her why, she said because the teller would have to pay for the money out of the salary she earned. My mom was compassionate and honest. But she was NOT saved at that point.
Eternal security, is NOT about what you do. It is about what Jesus did on the cross for us. That is the whole point of believing in Jesus. Anyone can be loving, compassionate, honest or act righteous.
But only those who believe in Jesus, and turn from their sins are saved. And then, we follow Jesus, we do not become a "reprobate."
Instead, we trust the Holy Spirit is transforming us into the image of Christ.
"Do not be conformed to this world,but be transformed by the renewal of your mind, that by testing you may discern what is the will of God, what is good and acceptable and perfect." Romans 12:2
"And we all, with unveiled face, beholding the glory of the Lord,are being transformed into the same image from one degree of glory to another. For this comes from the Lord who is the Spirit." 2 Cor. 3:18
In both verses above, the word "transformed" is in the passive tense in both the Greek and English. That means that it is something done TO US! It is not about something we do. We are commanded to cooperate, but in the end, it is the Holy Spsirit that does the work, just as it is the Holy Spirit who saves us, not our works.