בְּסַּאסְּאָ֖ה בְּשַׁלְחָ֣הּ תְּרִיבֶ֑נָּה הָגָ֛ה בְּרוּח֥וֹ הַקָּשָׁ֖ה בְּי֥וֹם קָדִֽים׃
In full measure, when Thou sendest her away, Thou dost contend with her; He hath removed her with His rough blast in the day of the east wind.
Ibn Ezra on Isaiah
בסאסאה. In measure. According to most commentators בסאסאה is a reduplication of סאה measure, like 23Root: טול :ירק.23Root: טול :ירק.ירקרק green (Lev. 13:49); מטלטלך Will carry thee away (22:17).
Rashi on Isaiah
when they sent them out, it strove with it When Egypt sent Israel out, it strove with it, the seah of the measure with its seah.