There are too many to fit in one post, so I've just added this link which deals with the basics. Please consider these before we get get too deep, as there's a lot more to consider.
Reformed Theology Memory Verses
Next I’ll address irresistible grace and perseverance of the saints in the same message here. Now I’ve already started explaining against this in my last post with Romans 2 where despite God’s kindness, tolerance, and patience He is leading the Gentiles to repentance but because of their unrepentant heart they are storing up God’s wrath and judgement on judgement day. Before I go any further into this subject I would like to address the verses that were provided in the link you quoted. John 6:37 is very simple. What many people fail to realize is that the Greek word translated to “comes or cometh” is only used in the present and imperfect tense. This is explicitly stated in the Greek lexicons. What this means is that only those who presently and continuously come to Him, He will not cast out. It doesn’t mean that anyone who has ever came to Him, He will not cast out because that would directly contradict John 15:2 and John 15:6 where Jesus says that The Father cuts off every branch in Me that beareth not fruit and He says anyone who does not abide in Me is cast away to wither and cast into the fire to be burned. So Jesus is specifically saying that some whom The Father has allowed to come to Him will not remain in Him and they will be cast away and cast into the fire to be burned. Now before someone starts to quote John 6:39 I’m going to explain that the word “will” in that verse also means desire. It’s the same word used in 1 Timothy 2:3-4 the only difference is this is the noun form of the word instead of the verb used in 1 Timothy. Obviously we know that God has not deemed that all men will be saved. God desires all men to be saved, it’s not something that God has declared to happen. John 6:39 is simply saying that it is The Father’s desire is that Jesus should lose none and that He raise them up on the last day.
The next verse I want to point out is Revelation 2:20-21.
“But I have this against you, that you tolerate the woman Jezebel, who calls herself a prophetess, and she teaches and leads My bond-servants astray so that they commit acts of immorality and eat things sacrificed to idols.
I gave her time to repent, and she does not want to repent of her immorality.”
Revelation 2:20-21 NASB
Now if grace were irresistible then Jezebel would not have been able to resist repentance. If Jezebel has not been granted grace then Jesus wouldn’t have expected her to repent even going so far as to give her time to repent because He knows that without grace she is utterly incapable of repentance. Jezebel is another example of Paul’s message in Romans 2. Jesus’ kindness and patience is leading her to repentance but because of her stubborn unrepentant heart she is storing up God’s wrath.
Another indication is in Jesus’ explanation of the parable of the sower.
“Those on the rocky soil are those who, when they hear, receive the word with joy; and these have no firm root;
they believe for a while, and in time of temptation fall away.”
Luke 8:13 NASB
Many people will say that anyone who falls away never truly believed. Well Jesus just said right here that some will believe and fall away. The sorcerer Simon Magus is a prime example. The scriptures say that Simon Magus heard the gospel and believed.
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But when they believed Philip preaching the good news about the kingdom of God and the name of Jesus Christ, they were being baptized, men and women alike. Even Simon himself believed; and after being baptized, he continued on with Philip, and as he observed signs and great miracles taking place, he was constantly amazed.”
Acts 8:12-13 NASB
Simon later fell away and fell to conjuring demons and practicing black magic. I won’t get into the details of that because they’re not recorded in the scriptures but they were recorded by the church.
Of course there’s always John 15:1-10 where Jesus tells His faithful 11 apostles to abide in Him and even explains the consequences of failing to abide in Him and even goes further by telling them what they can expect IF they abide in Him. We all know that these men were true believers, and yet Jesus felt it was necessary to tell them to abide in Him, explaining why, and the consequences of what will happen if they don’t, and what they can expect if they do. So if grace is irresistible, how is it possible for someone to fail to abide in Christ resulting in condemnation? No one can come to Christ unless they have been given grace by The Father. if grace is irresistible then John 15:6 is impossible.
I’ll give just one more example of falling from grace which is in Galatians 5:4.
“You have been severed from Christ, you who are seeking to be justified by law; you have fallen from grace.”
Galatians 5:4 NASB
It really doesn’t get any clearer than this. Grace is undoubtedly resistible and a person is capable of falling from grace and being severed from Christ. There’s ample evidence of this in the scriptures.