סימן רס"ו

Siman Two Hundred and Sixty-Sixסימן רסו "For his flocks he made booths [sukkos]" — and so on. V"ayakov N"asa S"ucosah V"ayiven — the initial letters spell Sivan — and so on. See Shulchan Aruch Even HaEzer, Siman 127, Paragraph 7 — where it is elaborated: that one is required to write the name of this month as Sivan in a divorce document. And therefore it seems in my humble opinion: that this too is the intention of Rabbainu here — namely: for the letters Yud-Vov in Sivan allude to the letters Vov-Yud of the word Vayakov — and likewise of the word Vayiven. For the Vov in both of these words is not of the essential root of the word. And therefore it needs to be alluded together with the Yud that is in the root of the word — as is understood.