Any heretic can claim to have the Holy Spirit. (And throughout Church history, heretics have claimed to have the Holy Spirit.) The gnosticism that the Church has always condemened as heretical disconnects form and matter, separating "word from witness", and grace from sacrament. In this way gnosticism denies the relation between Apostolic succession and authentic ordination. However, the one ordaining cannot give what he does not have. We know that the Apostles had the authority from Christ, and so we know that those ordained by the Apostles (and those in sacramental succession from the Apostles) have this authority. But those who do not have ordination from the Apostles, what authority do they have to tell us what the Gospel is, what the contents of the NT are, and what the proper interpretation of the Scriptures is? How do we know who has the Spirit? Gnostics claim that we know by a 'burning in our bosom', an entirely subjective experience. Another form of gnosticism claims to test the spirits by comparing a claim to the Scriptures. But this form of gnosticism presumes that it already knows the canon of Scripture, the authoritative interpretation of Scriptures [even though there are 20,000+ Protestant sects], and that there is no living Magesterium. So this form of gnosticism just pushes the subjectivism back a step, to the determination of canon and interpretation. It plucks the canon out of ahistorical thin air, ripping it from the hands of the Apostles and bishops by whose authority it was established and accepted.
The "one, holy, catholic and apostolic Church", has always rejected gnosticism. She determines who has the Spirit by way of succession. (cf. 1 John 4:6). The NT has authority in virtue of the authority of those who wrote it, approved it, and ratified it. Protestantism has no way to determine the NT canon. Each Protestant can determine for himself which texts belong to the NT. Don't like a book in the NT? Rip it out. Wish to add Chicken Soup for the Soul?, just stick it in. Without a living Magesterium, you are your own authority. You get to determine for yourself not only the interpretation of Scripture, but the very texts of Scripture. Just as you can make your own customized teddy bear, or Mini-Cooper, if you are a Protestant, you can make your own customized Bible. Why not? Who is to say what the canon is? You are not under the authority of all those fourth and fifth century bishops, so why do you follow them with respect to the NT canon? You are not under the authority of Luther and Calvin, so they don't determine for you what the canon must be. BUILD YOUR OWN CANON. Just as you can find 'Build your own Bear' stores in the mall, it is merely intellectual inertia and lack of creativity that we have yet to see Protestants open "Build your own Bible" stores in the malls.
-A8
Very true. We are most fortunate to be under the authority of Scripture, by the grace of God alone.
"...the restoration of the church is the work of God, and no more depends on the hopes and opinions of men, than the resurrection of the dead, or any other miracle of that description. Here, therefore, we are not to wait for facility of action, either from the will of men, or the temper of the times, but must rush forward through the midst of despair. It is the will of our Master that his gospel be preached. Let us obey his command, and follow whithersoever he calls. What the success will be it is not ours to inquire. Our only duty is to wish for what is best, and beseech it of the Lord in prayer; to strive with all zeal, solicitude, and diligence, to bring about the desired result, and, at the same time, to submit with patience to whatever that result may be." -- John Calvin
Who ordained Paul? Who ordained the Gentiles in Acts 10:47-48?
She determines who has the Spirit by way of succession.
How much evil has entered this church of yours "by way of succession"? Wouldn't a better standard be that which Jesus Himself was identified by?
Isa 8:20 To the Law and to the testimony! If they do not speak according to this Word, it is because no light is in them.
See also the longer version at Deuteronomy 13:1-5.