TgJ Is40:29 :יָהֵיב לְצַדִיקַיָא דִמשַלהַן לְפִתגָמֵי אוֹרָיתֵיה חָכמָא‏ : He gives wisdom to the righteous who are exhausted for/by(?) the words of His Torah
See the entire entry for šlhy vb. to weaken