Commentary for Isaiah 1:17

Learn It is punctuated ‘raphe,’ weak, without a dagesh. This is from the form לָמֹד, learn to do good. One who teaches himself is of the ‘kal’ form. Therefore, its imperative plural is voweled with a ‘chirik’ like אִמְרוּ, שִׁמְעוּ, but one who teaches others is of the form of the ‘heavy conjugation’ (pi’el) with a ‘dagesh,’ and if one comes to command a number of people, the word is voweled לַמְּדוּ. And so, דִּרְשׁוּ, from the form דְרשׁ, but אַשְּׁרוּ in which the ‘shin’ has a ‘dagesh,’ is from the ‘heavy conjugation,’ and from the form אַשֵּׁר ; therefore, the imperative plural is voweled with a ‘patach’ like בַּשְּׂרוּ, סַפְּרוּ, דַּבְּרוּ.

להיטב═היטב To do well. It is infinitive.

strengthen the robbed Heb. אַשְּׁרוּ חָמוֹץ. This is a Mishnaic term, אֲשַׁרְנוּהִי, “we have verified it” (Ketuboth 21a); “if I had strength (אֲיַשֵּׁר)” (Gittin 30b); “May your strength be strengthened (יִישַׁר)” (Shabbath 87a). Another explanation is: Lead him in the path of truth to acquire what rightfully belongs to him. An expression of: (Job 23:11) “My foot held its path (בֲּאֲשׁוּרוֹ)”; (Prov. 23:19) “And go (וְאַשֵׁר) in the way of your heart.”