אחל תת פחדך, "I shall begin to put the fear of you, etc." This verse contains a hint that the sun stood still for Moses during the battle against Og just as it stood still in Joshua's time. This is the opinion of the sages in Taanit 20 who say that there were three people on whose account the orbit of the sun was arrested. They were: Moses, Joshua, Nakdimon son of Gurion. The latter case is testified to by the Talmud. [The miracle was performed in order for Nakdimon not to have to pay a huge sum pledged to the Romans in exchange for water from their stores for the Jews in the event it would not rain by a certain date. Ed.]. We know that the sun was arrested in its orbit in response to a prayer by Joshua when he asked in Joshua 10,12: "let the sun remain still at Givon and the moon at Ajalon." This is followed in verse 13 by: "the sun stood half way up in the sky." How do we know that something similar occurred for Moses? Rabbi Eliezer points to the word אחל in our verse, and the same word in Joshua 3,7 where God promises Joshua to display his greatness to the people. God adds that "just as I was with Moses I will be with you." The implication is that the performance of the miracle of the sun standing still for Joshua will prove that he, just as Moses for whom the sun had also stood still, is great.
Rabbi Yochanan brings a different proof from the word תת. In our verse God says that He will begin to put the fear of Moses into the nations surrounding the Jewish people. In Joshua 10,12 that word תת also appears in connection with "silencing, or arresting" the sun. Rabbi Shmuel bar Nachmeni in Avodah Zarah 25 feels that the whole text of the verse is sufficient proof. Seeing that God promises to put the fear and dread of Moses into all the people under the sky, how was this to be accomplished simultaneously? By some manifestation of something supernatural in the sky, visible to all. What was it? The arrest of the orbit of the sun. This is the reason the Torah referred to היום הזה, i.e. all the nations of the world would become aware of this phenomenon on the same day.
Seeing that the continued existence of the terrestrial universe depends on the functioning of the orbits of the sun, this miracle was as great as the acts of creation described in Genesis. Even a brief interruption of the movements of the sun could lead to serious ecological damage to parts of the earth exposed at the time. The fact that both Joshua and Moses caused the sun's orbit to be arrested (for several hours in the case of Joshua) without negative fallout for the inhabitants of the earth caused people to become overawed by the power of Moses and Joshua respectively.
This miracle cannot be compared to that which occurred when King Chizkiyah of Yehudah asked that the hands of the sundial be reversed; this is why that King was not mentioned as in the same category as Moses, Joshua, and Nakdimon
(compare Tosafot Avodah Zarah 25). In that miracle the sun never stood still; it only traveled backwards for the appropriate amount of time, but it remained in motion. The word נקדה used by the Talmud in Taanit to described what happened to the sun for the sake of the three people mentioned is the same as the word נקודה, a stationary spot. That very word already makes it clear that what happened in those three instances was different from what happened at Chizkiyah's request
(compare Kings II 20,10-11).
Tanchuma Acharey Mot 9 focuses on the word דום "be silent," rather than עמוד, which appears in Joshua chapter 10. The sun is perceived as constantly praising the Almighty, i.e. its motion is the way in which it praises the Lord. If it stands still, this results in its temporarily ceasing to praise the Lord. It therefore cannot proceed when it remains silent. Its function is aptly described by David when he said in Psalms 113,3: "from the east (where it rises) until it sets the name of the Lord is praised by means of it." Seeing that this is the sun's function, i.e. to praise the Lord, Joshua commanded it to be silent, i.e. to cease to function. Arrest of its motion is simply a corollary. The Midrash there elaborates that the sun did not simply accept Joshua's command but demanded to know how it could be that a "minor" could command a "major?" It meant that seeing it had been created before man, how could man presume to issue orders to the sun? Joshua replied to this argument: "why should not a free (willed) person, even though junior, be able to give orders to a senior who has no freedom of choice?" Upon hearing this, the sun was silent and as a result its orbit ceased. This is the meaning of: "the sun stood in mid-heaven" (
Joshua 10,
13).