וַיַּבְרֵ֧ךְ הַגְּמַלִּ֛ים מִח֥וּץ לָעִ֖יר אֶל־בְּאֵ֣ר הַמָּ֑יִם לְעֵ֣ת עֶ֔רֶב לְעֵ֖ת צֵ֥את הַשֹּׁאֲבֹֽת׃
И он заставил верблюдов становиться на колени без города у колодца с водой во время вечера, когда женщины выходят за водой.
Chizkuni
ויברך הגמלים, “he made the camels kneel down.” Camels have two sets of knees. They therefore have to perform two acts of kneeling, before being able to drink. We have learned more details in the Talmud Chulin 76.
Rashbam
ויברך הגמלים, a camel has two knees one above the other; therefore it needs two motions to go down on its knees and because of its height it cannot drink before having thus lowered itself to the level of the trough. This is what the sages referred to in Chulin 76 when they said וכנגדו בגמל ניכר, that a spot known as the ארכובה in cattle is clearly recognisable on the foreleg of a camel.