כְּרֻבִים Ex. 25:18:20

[Isaac Fried]

We read there
וְעָשִׂיתָ שְׁנַיִם כְּרֻבִים זָהָב מִקְשָׁה תַּעֲשֶׂה אֹתָם מִשְּׁנֵי קְצוֹת הַכַּפֹּרֶת וַעֲשֵׂה כְּרוּב אֶחָד מִקָּצָה מִזֶּה וּכְרוּב אֶחָד מִקָּצָה מִזֶּה מִן הַכַּפֹּרֶת תַּעֲשׂוּ אֶת הַכְּרֻבִים עַל שְׁנֵי קְצוֹתָיו וְהָיוּ הַכְּרֻבִים פֹּרְשֵׂי כְנָפַיִם לְמַעְלָה סֹכְכִים בְּכַנְפֵיהֶם עַל הַכַּפֹּרֶת וּפְנֵיהֶם אִישׁ אֶל אָחִיו אֶל הַכַּפֹּרֶת יִהְיוּ פְּנֵי הַכְּרֻבִים
NIV: "And make two cherubim out of hammered gold at the ends of the cover. Make one cherub on one end and the second cherub on the other; make the cherubim of one piece with the cover, at the two ends. The cherubim are to have their wings spread upward, overshadowing the cover with them. The cherubim are to face each other, looking toward the cover"
where הַכְּרֻבִים = היא-כר-הוּא-ב-הם is from the root כרב, a member of good standing, of the Hebrew root family
גרב, חרב, כרב, קרב
which leads me to suspect that הַכְּרֻבִים are but הַקְרוֹבִים, the personal defense guard of a king, nearest to his body. The כְּנָפַיִם, 'wings', that they are spreading are possibly but the long tails of their uniform, designed to hide their swords, or, if needed, to cover the king.
The כְּרֻבִים of Gen. 3:24
וַיְגָרֶשׁ אֶת הָאָדָם וַיַּשְׁכֵּן מִקֶּדֶם לְגַן עֵדֶן אֶת הַכְּרֻבִים וְאֵת לַהַט הַחֶרֶב הַמִּתְהַפֶּכֶת לִשְׁמֹר אֶת דֶּרֶךְ עֵץ הַחַיִּים
are not mentioned as having wings.
Also, the מלאכי אלוהים, 'angels of God', of Gen. 28:12
וַיַּחֲלֹם וְהִנֵּה סֻלָּם מֻצָּב אַרְצָה וְרֹאשׁוֹ מַגִּיעַ הַשָּׁמָיְמָה וְהִנֵּה מַלְאֲכֵי אֱלֹהִים עֹלִים וְיֹרְדִים בּוֹ
NIV: "He had a dream in which he saw a stairway resting on the earth, with its top reaching to heaven, and the angels of God were ascending and descending on it"
are not going up and down the easy way by a flap of their wings, but rather by the hard way of clambering up and down a steep ladder.
The image of a כְּרוּב growing wings on his shoulders is possibly a later understanding, possibly influenced by the imposing and fantastic art of the east, as in 2sam. 22:11
וַיִּרְכַּב עַל כְּרוּב וַיָּעֹף
In 2Kings 7:29
וְעַל הַמִּסְגְּרוֹת אֲשֶׁר בֵּין הַשְׁלַבִּים אֲרָיוֹת בָּקָר וּכְרוּבִים
the כְרוּבִים appears to be some sort of an animal, possibly a flock of birds.

Isaac Fried, Boston University

[Isaac Fried]

The word עַקְרָב of Deut. 8:15
הַמּוֹלִיכְךָ בַּמִּדְבָּר הַגָּדֹל וְהַנּוֹרָא נָחָשׁ שָׂרָף וְעַקְרָב
NIV: "He led you through the vast and dreadful wilderness, that thirsty and waterless land, with its venomous snakes and scorpions"
bears a resemblance to כְּרוּב, but if we accept עַקְרָב as indeed meaning 'scorpion', then it is wingless.
Where do the wings come from?

Isaac Fried, Boston University