"I have not sent these prophets, yet they ran: I have not spoken to them, yet they prophesied.
But if they had stood in my counsel, and had caused my people to hear my words, then they should have turned them from their evil way, and from the evil of their doings." Jeremiah 23:21, 22
The biggest refutation of "Eternal Security" is that if "Eternal Security" is true, you will no longer need to FEAR God which is "Wisdom" and is an actual attribute of God (Isaiah 11). God specifies our need to fear Him all through the whole entire Bible. And Wisdom, God says, is "the principal thing." (Proverbs 4:7)
I more than anyone I know would love to say "I'm predestinated and there's NO WAY I could fall away, because when i was born again i was sealed with God's Holy Spirit and I'm the elect and was foreordained and nothing can pluck me out of God's hand and He who begun a work in my will finish it as the Bible says, 'He is the author and finisher' of our faith..." and so on and so on.
I would love for this to be true. But it's not. The Scriptures that are used are true, IN CONTEXT WITH THE WHOLE WORD OF GOD.
But let's make sure we understand the key words and what it says in the Greek. These definitions are from the Strong's concordance.
"Sealed" 4972. sphragizo sfrag-id'-zo from 4973; to stamp (with a signet or private mark) for security or preservation (literally or figuratively); by implication, to keep secret, to attest:--(set a, set to) seal up, stop.
"Predestinated" 4309. proorizo pro-or-id'-zo from 4253 and 3724; to limit in advance, i.e. (figuratively) predetermine:--determine before, ordain, predestinate. Four usages in the whole Bible.
"Elect" or "Chosen" (same exact Greek word) 1588. eklektos ek-lek-tos' from 1586; select; by implication, favorite:--chosen, elect.
As you can see, these words when closely examined, show that it is possible for one to be saved and then lose their salvation. But when we read the rest of the Bible it proves without any shadow of a doubt that one can fall away from God, into sin and ultimately wind up in Hell.
One definition of "Sealed" means "attest". "predestined" simply means "foreknowledge" and "Elect" means "Chosen" The "Elect" or "Chosen" are the people of God who the Apostles speak to in their Epistles. The Apostles warn these same "Elect" and "Chosen" that they need to "Strive, Press On, run the race with patience, Endure, Follow the Lord, Walk in the ways of the Lord, Grow in Grace, Put on the Whole Armor of God, seek God, Pray unceasingly, Pray Alway, Watch, fast, etc etc.
And these same "Predestinated" ones are warned specifically about falling away in these verses:
Hebrews 10: 26-31 " For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more sacrifice for sins,
27 But a certain fearful looking for of judgment and fiery indignation, which shall devour the adversaries.
28 He that despised Moses' law died without mercy under two or three witnesses:
29 Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant, wherewith he was sanctified, an unholy thing, and hath done despite unto the Spirit of grace?
30 For we know him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people.
31 It is a fearful thing to fall into the hands of the living God.
2 Peter 2:17-22
"These are wells without water, clouds that are carried with a tempest; to whom the mist of darkness is reserved for ever.
18 For when they speak great swelling words of vanity, they allure through the lusts of the flesh, through much wantonness, those that were clean escaped from them who live in error.
19 While they promise them liberty, they themselves are the servants of corruption: for of whom a man is overcome, of the same is he brought in bondage.
20 For if after they have escaped the pollutions of the world through the knowledge of the Lord and Saviour Jesus Christ, they are again entangled therein, and overcome, the latter end is worse with them than the beginning.
21 For it had been better for them not to have known the way of righteousness, than, after they have known it, to turn from the holy commandment delivered unto them.
22 But it is happened unto them according to the true proverb, The dog is turned to his own vomit again; and the sow that was washed to her wallowing in the mire.
1 Peter 4:17, 18 "For the time is come that judgment must begin at the house of God: and if it first begin at us, what shall the end be of them that obey not the gospel of God?"
"And if the righteous scarcely be saved, where shall the ungodly and the sinner appear?"
I could list many more verses proving my point but I believe these verses to be incredibly more clear than this teaching of "predestination" and "eternal security"