Thank you for the post.
You think God quit leading people at some point after either the scriptures were written or the canon was set?
Can you be a little more specific on when you think the Spirit stopped leading Christians?
The short answer is that this is one of those various issues of inference the Scripture is replete with.
As when, for example, it mentions Peter's wife's mother; the obvious inference being that she was his mother-in-law.
And that kind of thing is not like the "well, perhaps this" or "maybe that" which far too many nevertheless allow themselves to arrive at their conclusions about a thing on.
In contrast to that, an inference is based on what IS obvious.
Matthew 8:14 And when Jesus was come into Peter's house, he saw his wife's mother laid, and sick of a fever.
To your question, then, with a question...
What had been the purpose of the Spirit's leading?
Well "what saith the Scripture?" Gal. 4: 30, on that?
2 Samuel 23:2 The Spirit of the LORD spake by me, and his word was in my tongue.
Towards what end?
Well, what did Peter say about that?
What did he write as his life came to an end?
2 Peter 1:13 Yea, I think it meet, as long as I am in this tabernacle, to stir you up by putting you in remembrance; 1:14 Knowing that shortly I must put off this my tabernacle, even as our Lord Jesus Christ hath shewed me. 1:15 Moreover I will endeavour that ye may be able after my decease to have these things always in remembrance. 1:16 For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty. 1:17 For he received from God the Father honour and glory, when there came such a voice to him from the excellent glory, This is my beloved Son, in whom I am well pleased. 1:18 And this voice which came from heaven we heard, when we were with him in the holy mount.
He wrote that although he and his fellow Apostles had had that firsthand eyewitness...
2 Peter 1:19 We have also a more sure word of prophecy; whereunto ye do well that ye take heed, as unto a light that shineth in a dark place, until the day dawn, and the day star arise in your hearts: 1:20 Knowing this first, that no prophecy of the scripture is of any private interpretation. 1:21 For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost.
A more sure word?
Though obviously He had not had to; even the Lord Himself had submitted Himself to It's witness above that of His Own by then, VERY EVIDENT say so...
Luke 24:25 Then he said unto them, O fools, and slow of heart to believe all that the prophets have spoken: 24:26 Ought not Christ to have suffered these things, and to enter into his glory? 24:27 And beginning at Moses and all the prophets, he expounded unto them in all the scriptures the things concerning himself.
Just as Peter would later assert - that we have a more sure Word of Prophecy over the very fact of their having walked with the Lord Himself.
Notice once more how that it is ABOVE all else, even among His sign people: Israel...
Isaiah 8:18 Behold, I and the children whom the LORD hath given me are for signs and for wonders in Israel from the LORD of hosts, which dwelleth in mount Zion. 8:19 And when they shall say unto you, Seek unto them that have familiar spirits, and unto wizards that peep, and that mutter: should not a people seek unto their God? for the living to the dead? 8:20 To the law and to the testimony: if they speak not according to this word, it is because there is no light in them.
But moving on from all that for now, we read in...
1 Corinthians 13:8 Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away. 13:9 For we know in part, and we prophesy in part. 13:10 But when that which is perfect is come, then that which is in part shall be done away.
Note again, the intent of said prophecies, or telling forth of God's will - so that "we know.
What were they doing with all that Spirit's leading them in that 1st Century also?
1 Corinthians 14:37 If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord. 14:38 But if any man be ignorant, let him be ignorant. 14:39 Wherefore, brethren, covet to prophesy, and forbid not to speak with tongues.
What those 1st Century prophets at Corinth were doing was confirming that Paul's words were actually the Lord's.
Just as Peter had after the following...
Galatians 2:1 Then fourteen years after I went up again to Jerusalem with Barnabas, and took Titus with me also. 2:2 And I went up by revelation, and communicated unto them that gospel which I preach among the Gentiles, but privately to them which were of reputation, lest by any means I should run, or had run, in vain.
2:9 And when James, Cephas, and John, who seemed to be pillars, perceived the grace that was given unto me, they gave to me and Barnabas the right hands of fellowship; that we should go unto the heathen, and they unto the circumcision.
2 Peter 3:14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him in peace, without spot, and blameless. 3:15 And account that the longsuffering of our Lord is salvation; even as our beloved brother Paul also according to the wisdom given unto him hath written unto you; 3:16 As also in all his epistles, speaking in them of these things; in which are some things hard to be understood, which they that are unlearned and unstable wrest, as they do also the other scriptures, unto their own destruction.
As I have already noted, this is a much longer study (that a mere sounbyte hasn't any hope of doing justice to).
But you see this...
1 Corinthians 13:9 For we know in part, and we prophesy in part. 13:10 But when that which is perfect is come, then that which is in part shall be done away.
The opposite of that "in part" would be a FULL measure of it.
In stark contrast to that "in part" is 2 Timothy 3:16's All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: 3:17 That the man of God may be perfect, throughly furnished unto all good works.
Note the word "perfect."
Note also, its definition, now possible, at the end of Paul's own life - that the man of God might perfect: in other words "THROUGHLY furnished unto ALL good works."
And I am writing all this largely from memory.
Which is how memory works; but superstition concludes "that is the Spirit's leading."
It is not.
It is the mind's memory management system, given each of us by God, in Adam.
Note this in the following - way before He gave them, the Spirit, way before He even went to the Cross...
John 2:16 And said unto them that sold doves, Take these things hence; make not my Father's house an house of merchandise. 2:17 And his disciples remembered that it was written, The zeal of thine house hath eaten me up.
It took me a minute to let go of my own nonsense on that.
I know how all that works first hand.
The confirmation bias of simple ignorance of what the Scripture infers on this issues, by what it teaches.
And man o man is this offensive to the superstitious mind.
Only Believers within all "faiths" pull this pagan duality.
The duality of knowing very well, on the one hand, that they remember where their car keys are, simply due to the mind's memory management via association of things now related to one another, "by reason of use."
In contrast to the superstition, on the other hand, of erroneously concluding "o the Spirit brought this and that 'about God' to my mind..." or what have you.
Never mind all the constant hits and misses of that.
Anyway, this is my understanding of these things of the Lord, in light of His Word.
But as the writer of Hebrews as regards His things...
Hebrews 5:11 Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. 5:12 For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. 5:13 For every one that useth milk is unskilful in the word of righteousness: for he is a babe. 5:14 But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.
Acts 17: 11, 12.