“These are God's festivals that you must call out as sacred holidays at their appropriate times.”
The words “These are the festivals of God” (Eleh moadei Yud-Hey-Vav-Hey) spell out the word “Imma” with their first letters. Thus on a Festival the spiritual entities of the Cosmic Man and Cosmic Woman rise only to the level of Supernal Mother, but no higher. In addition, the Mother is represented by the expansion of God's name with aleph, like this: yud-vav-dalet, hey-aleph, and so on, with the gematria of 63. With the 10 letters of the expansion it makes 73, or the gematria of Yom Tov (Holiday) itself.
However, when you call out Holidays with your prayers, you allow the children (Man and Woman) to rise higher and come to the Supernal Father also. Thus the first letters of “them in their times,” (otam b'moadam) make the word Av (Father). On Shabbat the children go higher, to the Father, just because of Shabbat, “because it is holy.”
What is the meaning of all this? God has created the five spiritual entities in the world, of which we and our souls are a part. We allow them to find each other, and are blessed in return.
Art: Jozsef Rippl-Ronai - My Father And My Mother 1897