|The Sephirot in Jewish Kabbalah|
Yesod (Hebrew: יסוד "foundation") is a sephirah in the kabbalistic Tree of Life. Yesod is the sephirah below Hod and Netzach, and above Malkuth (the kingdom). It is the vehicle, from one thing or condition to another. It is the power of connection.
Yesod is the foundation upon which God has built the world. It also serves as a transmitter between the sephirot above, and the reality below. The light of the upper sephirot gather in Yesod and are channelled to Malkuth below. In this manner, Yesod is associated with a sexual organ. The masculine Yesod collects the vital forces of the sephirot above, and transmits these creative and vital energies into the feminine Malkuth below. Yesod channels, Malkuth receives. In turn, it is through Malkuth that the earth is able to interact with the divinity. 
It plays the role of collecting and balancing the different and opposing energies of Hod and Netzach, and also from Tiferet above it, storing and distributing it throughout the world. It is likened to the 'engine-room' of creation.
The third person of the Holy Trinity, the Holy Spirit, is the Christian counterpart of the Yesod. The Holy Spirit is seen by mainstream Christians as one Person of the Triune God, who revealed His Holy Name YHWH to his people Israel, sent His Eternally Begotten Son Jesus to save them from their Sins, and sent the Holy Spirit to sanctify and give life to his Church. The Holy Spirit is known as the aspect of god that sanctifies mankind, unifying God with it. Parallel to Yesod, which is the middle axis of the Sephirot, the Yesod is responsible for the powers of communication, connection and contact with external reality within the soul, unifying Malchut to the Sephirot itself, being the symbol of Human to God union. In the Christianism, the Holy Spirit is responsible for enacting the contact with Abraham, in the Christian Kabbalah, Yesod is known as the symbol for the covenant between Abraham and God and their pact.
- Miller, Moshe. "Netzach, Hod, & Yesod". Kabbalah Online. Chabad.org. Retrieved 6 August 2015.
- Grillet, Angela Moehrle de. "A JOURNEY THROUGH THE TREE OF LIFE". website. Retrieved 25 February 2013.
- "Catechism of the Catholic Church: GOD REVEALS HIS NAME".
- St. Thomas Aquinas (1920). The Summa Theologica: First Part - The Procession of the Divine Persons (second and revised edition (Literally translated by Fathers of the English Dominican Province) ed.).
- Pope Pius XII (1943). Mystici Corporis Christi.
- Ginsburgh, Yitzchak. "The Ten Sefirot: Divine Emanations". website. Retrieved 25 February 2013.