[This is just a copy-paste job from a Twitter thread I wrote the other day.]

In John 6, Jesus says, "All the Father gives me will come to me; and him who comes to me I will not cast out," and "No one can come to me unless the Father who sent me draws him." These verses take high place in a common argument that the passage teaches most of TULIP.

No one can come unless the Father draws? Total depravity.
The Father gives people to the Son before they can even come to Him? Unconditional election.
All of these given people will come? Irresistible grace.
Jesus will never cast them out? Perseverance of the saints.

Well...

In one sense, this passage certainly does provide material from which these points of Calvinism might be legitimately inferred. However, we should note that the context in John and the overall passage indicates a different primary referent.

I suggest that Jesus is speaking more about things going on at that moment in redemptive history than the order of salvation as such. It's the historia salutis, not the ordo salutis.

Who are those given by the Father to the Son, and when were they given? Note that the text nowhere specifically answers this, and eternity is never invoked with reference to the past, only with reference to the future (eternal life). Perhaps the context sheds light?

One of John's key themes is the division of responses to Jesus when He comes to His own. He came to His own people (Israel), but they largely did not receive Him. Yet some did receive Him, and we should see these as those who have been given to Him by the Father.

In John, this development is more of a revelation than a transformation. Jesus' coming has exposed the two sides already in Israel: those looking for the true kingdom of the Messiah and those seeking one of this world, either over its dead body or comfortably in its arms.

What's the point? Throughout much of John, when people are coming to Jesus, they're not coming from rank unbelief to belief, per an effectual calling and regeneration. They had already "heard and learned from the Father" (v. 45) before Jesus came. That's how they recognize Him.

The transition of those the Father has given to Jesus when they come to Him, then, is not from no-faith to faith but from faith in God's promised kingdom to faith in Jesus of Nazareth as God's promised King.

Similarly, the Father did not (in this text) give these people to the Son in eternity past. Rather, He gave them in Jesus' ministry, entrusting the faithful remnant to His Son that His Son might accomplish the salvation planned for them and so keep Israel from wholly perishing.

The point of the passage is redemptive historical: Jesus' apocalyptic arrival shines a spotlight on Israel's division between the truly and the falsely faithful. Those who have heard and learned from the Father under the Old Covenant are given to the Son.

They will come to Jesus, and He will save them. But those who do not come to Him were already children of the devil in the house of God before He came, and they will perish now that they have been exposed for what they are.

(As a side note, though Jesus says He will never cast out anyone the Father gives Him, if we take this passage in connection with John 15, we might also ask whether Jesus leaves open the possibility that the Father may remove them, contra an "eternal security" type reading.)

In the end, you can still probably deduce even from this account support for the Calvinist ordo. It still seems right here to note that no one can come to Jesus without God's grace, that when the Father chooses someone they will indeed believe, etc.

But such extended doctrinal inferences should remain exactly that—inferences—rather than our primary account of what John is telling us about what Jesus had to say. If we keep this ordering straight, it prevents a lot of common pitfalls.