מַשְׂכִּ֗יל לְאָ֫סָ֥ף הַאֲזִ֣ינָה עַ֭מִּי תּוֹרָתִ֑י הַטּ֥וּ אָ֝זְנְכֶ֗ם לְאִמְרֵי־פִֽי׃
亞薩的訓誨詩。我的民啊，要留心聽我的教導；你們要側耳聽我口中的話語。
Rashi
ויט שכמו AND HE INCLINED HIS SHOULDER — he lowered his shoulder; similar are, (2 Samuel 22:10) “He bowed (ויט) the heavens” and (Psalms 78:1) “Incline (הטו) your ear”. Onkelos, however, explains it differently: HE BOWED HIS SHOULDER to wage wars and to conquer new districts — for he (Issachar) dwelt on the marches — AND the enemy BECAME subject to him AS A SERVANT TO PAY TRIBUTE.