Shmoth 5.2 “And Pharaoh said: ‘Who is the L-RD, that I should hearken unto His voice to let Israel go? I know not the L-RD, and moreover I will not let Israel go.’
Shmoth 6.1″And the L-RD said to Moses, “Now you will see what I will do to Pharaoh, for with a mighty hand he will send them out, and with a mighty hand he will drive them out of his land.””
RASHI: Now you will see, etc.: You have questioned My ways [of running the world, which is] unlike Abraham, to whom I said, “For in Isaac will be called your seed” (Gen. 21:12), and afterwards I said to him, “Bring him up there for a burnt offering” (Gen. 22:2), yet he did not question Me. Therefore, now you will see. What is done to Pharaoh you will see, but not what is done to the kings of the seven nations when I bring them [the children of Israel] into the land [of Israel]. — [from Sanh. 111a]
It has been taught: R. Eleazar son of R. Jose said: I once visited Alexandria of Egypt and found an old man there, who said to me, ‘Come, and I will shew thee what my ancestors did to thine: some of them they drowned in the sea, some they slew by the sword, and some they crushed in the buildings.’22 And for this Moses was punished,23 as it is said, For since I came to Pharaoh to speak in thy name, he hath done evil to this people,’ neither hast thou delivered thy people at all.24 Thereupon the Holy One, blessed be He, said to him, ‘Alas for those who are gone and no more to be found! For how many times did I reveal Myself to Abraham, Isaac, and Jacob by the name of El Shaddai,25 and they did not question my character,26 nor say to Me, What is Thy name? I said to Abraham, Arise, walk through the land in the length of it, and in the breadth of it,’ for I will give it unto thee:27 yet when he sought a place to bury Sarah, he did not find one, but had to purchase it for four hundred silver shekels; and still he did not question My character. I said to Isaac, Sojourn in this land, and I will be with thee, and will bless thee:28 yet his servants sought water to drink, and did not find it without its being disputed, as it is said, And the herdmen of Gerar did strive with Isaac’s herdmen saying, The water is our’s;29 still he did not question My character. I said to Jacob, The land whereon thou liest, to thee will I give it, and to thy seed:30 yet he sought a place to pitch his tent and did not find one until he purchased it for an hundred kesitah;31 nevertheless he did not question My character; nor did they say to me, What is Thy name?32 And now thou sayest to Me, Neither hast thou delivered thy people at all. [Therefore] Now shalt thou see what I will do to Pharaoh:33 thou shalt behold the war against Pharaoh, but not the war against the thirty one kings.’34
Note 32 The emphasis laid here upon the name of God, the virtue ascribed to the Patriarchs for refraining to ask it, and the reproach that Moses had wished to know it, are due to the fact that God’s name was regarded as more than a mere title of distinction. It represented His character, His Attributes, and the relationship in which He stood to His people. Consequently, to refrain from asking after God’s name was the equivalent of displaying complete confidence in Him, without examining his character closely to see whether His promises were reliable; whilst to ask it was to betray a lack of confidence.