5 The beast was given a mouth to utter proud words and blasphemies and to exercise its authority for forty-two months.

Read Revelation 13:5 Using Other Translations

And there was given unto him a mouth speaking great things and blasphemies; and power was given unto him to continue forty and two months.
And the beast was given a mouth uttering haughty and blasphemous words, and it was allowed to exercise authority for forty-two months.
Then the beast was allowed to speak great blasphemies against God. And he was given authority to do whatever he wanted for forty-two months.