That the said Quinbus Flestrin, contrary to the duty of a faithful subject, is now preparing to make a voyage to the court and empire of Blefuscu, for which he has received only verbal license from his imperial majesty; and, under colour of the said license, does falsely and traitorously intend to take the said voyage, and thereby to aid, comfort, and abet the emperor of Blefuscu, so lately an enemy, and in open war with his imperial majesty aforesaid.
" ’That, whereas certain ambassadors arrived from the Court of Blefuscu, to sue for peace in his majesty’s court, he, the said Flestrin, did, like a false traitor, aid, abet, comfort, and divert, the said ambassadors, although he knew them to be servants to a prince who was lately an open enemy to his imperial majesty, and in an open war against his said majesty.
There are no more uses of "abet" in the book.
Show samples from other sources
The man who could not be discourteous to a ground-squirrel had sat in the courthouse abetting the cause of grubby-minded little men.
Harper Lee -- Go Set a Watchman
Not telling her is tantamount to aiding and abetting the enemy.