Devarim (Deuteromony) 18:20
Ach hanavi asher yazid ledaber davar bishmi et asher lo-tsivitiv ledaber va’asher yedaber beshem elohim acherim umet hanavi hahu.
But the prophet, who shall speak a word presumptuously in my name, which I have not commanded him to speak, or who shall speak in the name of other gods, that same prophet shall die.

A person is forbidden to give a prophecy in the name of YHVH, when in fact, YHVH never instructed him to give such a prophecy. How do we know if a prophesy was not from YHVH?

If you say in your heart, How shall we know the word which YHVH has not spoken? when a prophet speaks in the name of YHVH, if the thing doesn’t follow, nor happen, that is the thing which YHVH has not spoken: the prophet has spoken it presumptuously, you shall not be afraid of him. (Devarim/Deuteronomy 18:21-22)

Therefore if what was prophesied never happens, then it was spoken presumptuously, and was not from YHVH.

Yirmeyahu (Jeremiah) 14:14  Then YHVH said to me, The prophets prophesy lies in my name; I didn’t send them, neither have I commanded them, neither spoke I to them: they prophesy to you a lying vision, and divination, and a thing of nothing, and the deceit of their own heart.

Here is says that such prophesies come from either a lying vision, or the deceit of their own heart. A lying vision may be very well from the enemy of our soul.

Therefore, we should be careful about saying, "Thus says YHVH...." if we give a word of prophesy.

I do believe that there is a gift of prophesy among the congregations now.

1 Corinthians 14:32  The spirits of the prophets are subject to the prophets.

We have the ability with the help of Ruach HaKodesh to test a prophesy before we share it.

1 Corinthians 14:29  Let the prophets speak, two or three, and let the others discern.

And we can discern and test the prophesy when we hear it.