Hi Saxon,
"No one else can pluck them away, but a believer himself can do it." Think about what you are purposing; that a true Christian has more power than anyone else in the universe. No one, and that includes the sheep can remove himself from the Shepherd's strong grip. In view of such ***urance, it is odd that people should surmise that a true sheep of Christ could or would decide that he doesn't want to be a sheep any longer, and could remove himself from his Father's hand. The argument will not stand. The words "no one" are absolute. They do not allow for any exception. The inspired text does not say "no one except the christian himself" - and neither should we.'
The verses that you are looking at, John 10:28 and 29 are quite clear on what they are saying. Neither shall any man pluck them out of my hand. No man is able to pluck them out of my Father's hand. Jesus is clearly speaking of one person plucking another person out of his hand or the Father’s hand. It is totally impossible. What is possible is for a person to depart from the living God. (See Hebrews 3:12) What is possible is for a person to be hardened through the deceitfulness of sin. (See Hebrews 3:13) What is possible is for a person to let go of the beginning of our confidence before the end. (See Hebrews 3:14)

Why would anyone think that a Christian has more power than any on else in the universe when in John 10:29 Jesus states that the Father is greater than all?

If a sheep cannot remove himself from the Shepherd's strong grip, what is the purpose of the parable of the LOST sheep? Is Jesus talking about nothing or just to hear himself talk?

Did you not read the following when I last addressed the thought that a Christian would decide to depart from the living God? It is the same answer.

When a person is a believer they do not want to lose their salvation. There is a devil that is out there trying to deceive and deceiving those that believe. It is the lost that are already deceived but the saved are the targets for deception. (See Deuteronomy 11:16, Luke 21:8, and 2 Timothy 3:13) If it were not possible for the saved to be deceived, then why the warnings to Christians to be not deceived? 1 Peter 5:8 warns us that the devil is out to devour anyone that he can. The lost are already devoured.
The Christians that are the saved at the first resurrection did persevere to the end but there those that started off but did not persevere to the end. Luke 8:13 states this clearly. They received the word with joy and after a while they fall away.

When they fall away the Holy Spirit leaves them as they are not saved any longer. There is no scripture that says the Holy Spirit will stay in a person that has gone back to sin. The Holy Spirit will continue to convict that person that has fallen away but he does not dwell in sinners.

People do not decide to not be sheep anymore, they die. The wages of sin is still death, not a change of species.

It is unfortunate that you are not willing to hold fast to the words of Hebrews 3:12 as tight as you do when you take “no one” out of context and cling to that to support the unsupportable OSAS false doctrine.

John 10:28 And I give unto them eternal life; and they shall never perish, neither shall any man pluck them out of my hand.
John 10:29 My Father, which gave them me, is greater than all; and no man is able to pluck them out of my Father's hand.

Hebrews 3:12 Take heed, brethren, lest there be in any of you an evil heart of unbelief, in departing from the living God.
Hebrews 3:13 But exhort one another daily, while it is called To day; lest any of you be hardened through the deceitfulness of sin.
Hebrews 3:14 For we are made partakers of Christ, if we hold the beginning of our confidence stedfast unto the end;

Deuteronomy 11:16 Take heed to yourselves, that your heart be not deceived, and ye turn aside, and serve other gods, and worship them;

Luke 21:8 And he said, Take heed that ye be not deceived: for many shall come in my name, saying, I am Christ; and the time draweth near: go ye not therefore after them.

2 Timothy 3:13 But evil men and seducers shall wax worse and worse, deceiving, and being deceived

1 Peter 5:8 Be sober, be vigilant; because your adversary the devil, as a roaring lion, walketh about, seeking whom he may devour:

Luke 8:13 They on the rock are they, which, when they hear, receive the word with joy; and these have no root, which for a while believe, and in time of temptation fall away.