Musar zu Bamidbar 22:20

Compare the author of the Akeidat Yitzchak on that subject. He describes the word as similar in meaning to אך, or רק, similar to Deut. 15,4, אפס כי יהיה בך אביון, "but there will be amongst you someone who is destitute, etc."

We observe that the whole subject matter revolves around the Ineffable Name, the name representing G–d's Essence. It seems evident that Yitro knew something about the name of G–d, and this is why he said: "Now I know that י-ה-ו-ה is greater than any אלוהים (Exodus 18,11)." His statement included both idols and other aspects of G–d's names. Our sages have reported that Yitro in his search for truth had not omitted a single one of the religions practised during his time (Mechilta). He first came to the conclusion that there are several names i.e. manifestations of the true G–d, and that there was also a name that signified G–d's ability to effect changes in the laws of nature. He arrived at the conclusion that the four-lettered Ineffable Name was that Name.