1. Peter clearly says that in the last days God shall pour out His Spirit. Though he applied the verse to indicate the outpouring of God's Spirit at his own time, last days would mean this time period as well (dual application)

Acts 2:17 - 18: And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy:

3. The Revelation speaks of prophecy in the Last days:

Revelation 10:5, 6, 7: And the angel which I saw stand upon the sea and upon the earth lifted up his hand to heaven, And sware by him that liveth for ever and ever, who created heaven, and the things that therein are, and the earth, and the things that therein are, and the sea, and the things which are therein, that there should be time no longer: But in the days of the voice of the seventh angel, when he shall begin to sound, the mystery of God should be finished, as he hath declared to his servants the prophets.

1. Peter clearly says that in the last days God shall pour out His Spirit. Though he applied the verse to indicate the outpouring of God's Spirit at his own time, last days would mean this time period as well (dual application)

Acts 2:17 - 18: And it shall come to pass in the last days, saith God, I will pour out of my Spirit upon all flesh: and your sons and your daughters shall prophesy, and your young men shall see visions, and your old men shall dream dreams: And on my servants and on my handmaidens I will pour out in those days of my Spirit; and they shall prophesy:

This is taken from the book of Joel where it is explicit that the passage is about the current day rather than the days of the apostles.

Joel 2:28 - 31: And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, your old men shall dream dreams, your young men shall see visions: And also upon the servants and upon the handmaids in those days will I pour out my spirit. And I will shew wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and the terrible day of the LORD come.

To know what time this verse is talking about, we turn to Jesus who quotes the second part of the verse:

Mark 13:24 - 26: But in those days, after that tribulation, the sun shall be darkened, and the moon shall not give her light, And the stars of heaven shall fall, and the powers that are in heaven shall be shaken. And then shall they see the Son of man coming in the clouds with great power and glory.

This clearly states that the sun darkening, moon not giving light will happen just before the second coming of Jesus Christ.

3. Jesus' warning clearly explains that there will be Gifts of the Holy Spirit in the Last days:

Matthew 24:24: For there shall arise false Christs, and false prophets, and shall shew great signs and wonders; insomuch that, if it were possible, they shall deceive the very elect.

The Following are clear from this verse:

• There will be false prophets in the Last Days
• The false prophets will show great signs and wonders
• Many will be deceived - even among the elect

From the facts above, we can easily see that the warning (not to get deceived) and the predicted result (many will get deceived) would not make sense if there were no true prophets who will be showing true authentic signs. If there would be no true prophets, then it would make more sense for Jesus to warn against anyone who claims to be a prophet and to not believe any sign shown by them. A warning of this kind would have been very hard to ignore and only a very few only would have been deceived (if at all).

The fact that even the very elect get deceived shows that the false prophets and the signs shown by them so closely resemble the true prophets that it is very hard to discern between them.

tl;dr: There is no need to warn against duplicate if no original exist - infact it makes no sense to do so.

4. The Revelation speaks of prophecy in the Last days:

Revelation 10:5, 6, 7: And the angel which I saw stand upon the sea and upon the earth lifted up his hand to heaven, And sware by him that liveth for ever and ever, who created heaven, and the things that therein are, and the earth, and the things that therein are, and the sea, and the things which are therein, that there should be time no longer: But in the days of the voice of the seventh angel, when he shall begin to sound, the mystery of God should be finished, as he hath declared to his servants the prophets.

The word again means anew in the original tongue - This would mean that there would be new prophecies (hence prophets) when the events described in the chapter takes place.

5. God has promised to send Elijah before the Great and Terrible day of the Lord:

Malachi 4:5 - 6: Behold, I will send you Elijah the prophet before the coming of the great and dreadful day of the LORD: And he shall turn the heart of the fathers to the children, and the heart of the children to their fathers, lest I come and smite the earth with a curse.

Reading verses 1 and 2 of Malachi, we find that the great and terrible day of the Lord is the day when the earth shall burn as an oven - pointing to the final destruction of the wicked. So even though this is applied to John the Baptist, this has another application at the end of time.