קבלה אויף תהילים 145:17

It thus is incumbent that you contemplate and understand that, in and of themselves, all the supernal ministers are deficient and lacking, unless HaShem-יהו״ה, blessed is He, grants them food and sustenance. Know that all the angelic ministers and their nations receive their sustenance from the first letter of the Name HaShem-יהו״ה, blessed is He. This is the secret of the verse,²¹²Psalms 145:16 “You open Your hand-Yadecha-ידיך, and satisfy the desire of all the living,” which is to be understood as, “You open Your Yod-יודי״ך.”²¹³Also see Tikkunei Zohar 7b