And furthermore: ‘All who bend the knee, bend at ‘Blessed’...’cxxxviiBT Berakhot 12a They have indeed established, that one should include in it the ten sephirot, which are: YOD QE VAV QE, which are: the letter Khaf כ from ‘baruKh’ (blessed) – Keter, the letter Reish ר of: (Ps. 111:10) Reishyt (beginning) – Ḥokhmah, the letter Beiyt ב (=2) are two Heis – Higher and Lower Shekhinah, the letter Vav ו (=6) – six sephirot. Behold ten.
And because of it, it is stated: (Gen. 14:20) And blessed is the EL Most High... etc... and he gave him a tenth of everything.