@FromOffTheStreets
Can a child of God lie? Yes, the Bible warns him not to lie (Col. 3:9)
All liars will have their place in the lake that burns with fire and brimstone (Rev. 21:8).
Can a child of God get drunk? Yes, he is told not to get drunk (Eph. 5:18). 3. But no drunkard can enter into the kingdom of heaven.
Can a child of God commit fornication? Yes. Christians are told to flee from it.(1 Cor. 6:18) Fornicators cannot inherit the kingdom of God (1 Cor.6:9)
It appears that real Christians can and did commit real sins that they needed to repent of and to ask God to forgive them (conditional) so they may continue to "walk in the light." (where God's grace and mercy is)
Maybe your verse is teaching that no one can pluck you out of his hand...except you. If you refuse to meet the conditions of remaining faithful. (repentance and prayer )
The choice of sinning isn't because your conversion wasn't sincere, but because you're human and fall into temptation. All have sinned and continue to sin. Sin separates one from God.
The guarantee he gives in that verse (eternal life ) is gone when you do not meet the conditions of what the scriptures teach a faithful Christian must do to continue to remain in his hand where grace, mercy and forgiveness are. Eternal life in your verse is not guaranteed to the unfaithful. The one who continues in sin. He gets entangled and is overcome. He's in worse shape now than before he became a Christian. I don't think the Bible teaches his reward is eternal life.