תְּחִלַּ֥ת דִּבְרֵי־פִ֖יהוּ סִכְל֑וּת וְאַחֲרִ֣ית פִּ֔יהוּ הוֹלֵל֖וּת רָעָֽה׃
El principio de las palabras de su boca es necedad; y el fin de su charla nocivo desvarío.
Radak
(Mad) fools (הוללים) shall not stand before Thine eyes: – The significance of הוללים is sometimes that of folly, as (in the passages) “And he played the fool in their hands” (1 Sam. 21:14); “I said it is foolish” (Eccles. 2:2); and sometimes it is used with the significance of wickedness, as (in the passage) “mischievous madness” (הוללות) (ibid. 10:13), and similar instances. And in this sense (is the clause to be taken here)-(Mad) fools shall not stand before Thine eyes, as he proceeds to say
Rashi
and be like madmen an expression of madness, they shall be mad.