Arose one elder – he began a discourse and said: ‘Hei ה specifically has within it three Vavs ו (=18), which are the 18∞ḥaiy blessings, like this:, of which it is stated: (Prov. 10:6) Blessings are upon the head of ‘the righteous-one’...
What is the head of the righteous-one? This is the Middle Pillar, in which reside the 18 blessings of higher Hei ה, and from where they are extended to the lesser Hei ה, by means of the Righteous-One (tzadiq).
And because of this, ‘body (Tiperet) and covenant (Yesod) are considered as one.’clxxiiiSee Sepher ha-Bahir Ot 168