"at that time": An analogy: The men of a province ask their king to make their province a colony (and exempt from taxes). Once, when two of his foes fell before it, they said: Now is the time to ask the king to grant our request. Similarly, Moses asks the Holy One Blessed be He to be allowed to enter Eretz Yisrael. When he sees Sichon and Og fallen before him, he says: This is the time to ask that my request be granted, and this is the intent of "at that time."
(Ibid.) "to say": This is one of the times when Moses says to the L-rd: Tell me whether or not You will grant my request. Similarly, (Shemoth 17:4) "And Moses cried out to the L-rd, to say: What can I do to this people?" What is the intent of "to say"? Apprise me of whether or not I will fall into their hand. Similarly (Ibid. 6:12) "And Moses spoke before the L-rd, to say": Apprise me whether or not You will redeem them. Similarly, (Bamidbar 12:13) "And Moses cried out to the L-rd to say": Apprise me whether or not You will heal her. Similarly, (Ibid. 27:15) "And Moses spoke to the L-rd, to say": Apprise me whether or not You will appoint leaders over them. Thus, here, "at that time, to say": Apprise me whether or not I will enter the land.