[MurphsLaw]

John 10: 27 My sheep hear my voice, and I know them, and they follow me: 28 and I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand. 29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father’s hand. 30 I and my Father are one.

Jesus puts His teaching in the present tense, thus when He says 'neither shall any man pluck them out of my hand" He has issued a guarantee that in this life a man who is in His hand cannot be removed from His hand, and that includes the man himself.

Obviously God would not be so omnipotent if there was a stronger power to take (pluck) something from or away from God's hands. Maybe that wasn't so apparent in those early days.

But when you say..." that included man himself."...you're offering your opinion, in thinking that man has no capability of walking away from God.
It actually happens very often, usually a result of a tragedy. I have experienced this first hand in my family.
But nowhere in those verses do you read anything about not being able in removing themselves from God, insofar as you can make that claim.
It would be a stupid thing to do, walk away from God, but it is possible. Your just reading back into scripture your present day faith ideals to make that claim sem possible to you.

And if you read any of Sunday's Prodigal Son parable, you would see it as a cautionary tale against exactly that which you suggest is not possible.

Do you not think the Prodigal walked away from the Father then?

[MHGinTN]

Catholic, was the prodigal son still a son even as he was immersed in the sin he eventually walked away from to return to the Father? Think, Catholic. There is no once a year every year remembrance of sin to be dealt with. Jesus dealt with ALL of it through His blood, establishing a new covenant forever.

[MHGinTN]

Do two things: first, locate when in His ministry Jesus gave the parable, and second to whom did He address that story? Israel has walked away from Messiah, but Messiah is waiting for them to return one day.

Try a different gotcha.

[Luircin]

Does unrepentant sin and walking away from the Father apply to entire church bodies as well?

Because let me tell you, there are two very big unrepentant sins committed by Catholicism right off the top of my head.

[Luircin]

Snark about Catholicism’s sins aside, here’s the problem.

Catholicism doesn’t welcome the sinner back with joy. Catholicism says, “Sure you can come back, once you spend hundreds of years being tortured in Purgatory.”

[imardmd1]

>> But when you say..." that included man himself."...you're offering your opinion, in thinking that man has no capability of walking away from God. <<

Scripture says not. Paul says not. MHGinTN says not. Fala says not(!):

"But we^{born-anew non-Catholics} are not of them^{Romanly catechized Catholics} who draw back unto perdition; but of them^{OSAS convinced} that believe to the saving^{by the Savior Alone} of the soul" (Heb 10:39 AV; superscripts interpretive explanations added). 

>> It actually happens very often, usually a result of a tragedy. I have experienced this first hand in my family. <<

Your opinion is based on an unscriptural but catechised false assumption. What you apparently have not considered that the God-inspired Scripture is quite correct throughout from the beginning to its completion (at the time of Beloved John); nor of the fulfillment and abrogation of the Law Covenant by Jesus at the Cross, and finalized by the propitiation of man's sins by our High Priest in the offering of His Incorruptible Blood One-time Sacrifice before the Eyes of Our Heavenly Father, the same Blood Ever-fresh upon the Mercy Seat before Him, forever.

Thus, most probably your relative DID walk away from God's Gift, not trusting that whatever The Mighty Righteous God decides to allow to happen, results in good. ALWAYS.

And thus, your relative was not saved by infant baptism, nor by being catechized by another non-believer, nor saved by his/her own works, presumtively not by "Last Rites" applied by someone else either, but not personally and deliberaately casting ALL his/her cares upon Jesus (1 Pet. 5:7) accepting Salvation comprising Eternal Never-ending Absolute Life attainable by faith/change-of-mind Alone, the remedial trust wholly in Jesus Alone (2 Pet. 3:9,15), as confirmed by knowledge from Scripture Alone.

And thus to Hell for The Disbelieving, as the Jews mind-set was in John 10:22-41; announced by the lips of the God-Incarnate Messiah Alone, exercising Sword of the Spirit to separate the dead souls from their dead spirits.

Are you defying Heb. 10:39, which excludes true God-saved children from Heb. 6:6 and 10:26?