This verse begins the fourfold purpose of the "sea" beast. It is to
And there was GIVEN to him a MOUTH speaking ARROGANT WORDS and BLASPHEMIES;
It is not enough that the "sea beast" (Antichrist) exists, but now it is given a mouth. Remember that the devil has been kicked out of heaven (Revelation 12:9), and therefore has no more access to God. So the most that he can do is SPEAK OUT on earth. He will be a slick orator, and people will hang on every arrogant and blasphemous word.
Check out the influence that his word will have (2 Thessalonians 2:1-12).
and AUTHORITY to act for forty-two months WAS GIVEN to him.
God permits this kind of talk to go on for 42 months (Revelation 11:2). The time period is the same as 3 1/2 years (Revelation 12:14) or 1260 days (Revelation 12:6).
Watchman Nee points out in his book "Come, Lord Jesus" that 42 is 7 times 6. Seven is the perfect number (creation completed, etc.), while six is the Satanic number (verse 18). Hence 42 as a conflict between these two numbers results in wandering (during the Exodus, Israel passed 42 stations as written in Numbers) and judgment (42 lads killed (2 Kings 2:23-25)). This 42 month period during the tribulation is no different.....people deceived (wandering, verse 14), and if not deceived, killed (judgment, verse 15).