וִידֵ֤י מֹשֶׁה֙ כְּבֵדִ֔ים וַיִּקְחוּ־אֶ֛בֶן וַיָּשִׂ֥ימוּ תַחְתָּ֖יו וַיֵּ֣שֶׁב עָלֶ֑יהָ וְאַהֲרֹ֨ן וְח֜וּר תָּֽמְכ֣וּ בְיָדָ֗יו מִזֶּ֤ה אֶחָד֙ וּמִזֶּ֣ה אֶחָ֔ד וַיְהִ֥י יָדָ֛יו אֱמוּנָ֖ה עַד־בֹּ֥א הַשָּֽׁמֶשׁ׃
Namun tangan Musa menjadi berat. Lalu mereka mengambil sebuah batu dan meletakkannya di bawahnya, dan ia duduk di atasnya. Harun dan Hur menopang tangannya, seorang di sisi yang satu dan seorang lagi di sisi yang lain, sehingga tangannya tetap teguh sampai matahari terbenam.
Bartenura
מקום שנעשו בו נסים – such as the place where the Israelites crossed the Sea of Reeds and the stream of Arnon (see Numbers, chapter 21, verses 13 and following), and the fords of the Jordan River [where the Israelites crossed – see Joshua, chapter 3 verse 14 and following] the stone on which Moses, of blessed memory, sat when he fought the war against Amalek (see Exodus chapter 17, verse 12) and other similar occurrences. And public miracles such as these require everyone to recite a blessing, but individual miracles such as person who sees a place where a [personal] miracle had occurred for him, he himself is obligated to recite a blessing, “Praised [Are You, O LORD] who performed for a miracle in this bless,” and his son and grandson are obligated to recite the blessing, “Praised [Are You, O LORD] who performed a miracle for my ancestors in this place.” And all these blessings of our Mishnah require the mention of the Name of God and His Sovereignty – for any blessing which lacks the mention of God’s name and His sovereignty is not a blessing.
Ibn Ezra
The heh in the word spilled takes the place of the ordinary plural indicator, as in “my steps had slipped” [Psalms 73: 2]. There is also a homiletic explanation to the effect that the verb became singular (since the word “hand” is feminine, in most cases [see comment on Exodus 17: 12]).
Kli Yakar
And perhaps it alludes to weakness of hands that they weakened their hands from the Torah which was given from hand to hand, and from prayer which is through the lifting of hands, and from the attribute of acts of kindness which is something given from hand to hand. And evidence for this is from what it says, and Aaron and Hur supported his hands, in order to strengthen these three pillars upon which the house of Israel is established. And these three pillars were upheld by the three shepherds: Moses, Aaron, and Miriam, in whose merit God gave them manna, the well, and the clouds of glory. The manna was in the merit of Moses, for the Torah was only given to those who ate the manna. And the well, which supplied all their needs, was in the merit of Miriam who supplied food for the children, as it is said, and they kept the children alive. And the clouds of glory were in the merit of Aaron, who was occupied with the service of the sacrifices which caused the Divine Presence to dwell among Israel, and the cloud of the Lord was upon the Tabernacle.
And when Amalek heard of Aaron’s death, and that the clouds of glory had departed, then he came to fight with them, as is found in the portion of Chukat (Numbers 21:1). And from there is evidence that Aaron’s merit stood for Israel to save them from Amalek, who was always a strap of rebellion for Israel. Therefore, in this war, Moses wanted his hands to be steady through reminding them of the merit of these three pillars. And therefore Moses stood in the middle with the merit of receiving the Torah in his hand, and Aaron and Hur supported his hands from this side and that side, because Aaron had the merit of the service in his hand, and Hur, the son of Miriam, had the merit of acts of kindness in his hand.
And when Amalek heard of Aaron’s death, and that the clouds of glory had departed, then he came to fight with them, as is found in the portion of Chukat (Numbers 21:1). And from there is evidence that Aaron’s merit stood for Israel to save them from Amalek, who was always a strap of rebellion for Israel. Therefore, in this war, Moses wanted his hands to be steady through reminding them of the merit of these three pillars. And therefore Moses stood in the middle with the merit of receiving the Torah in his hand, and Aaron and Hur supported his hands from this side and that side, because Aaron had the merit of the service in his hand, and Hur, the son of Miriam, had the merit of acts of kindness in his hand.