The Torah Text
Balaam, a foreign prophet hired by the Moabite king Balak to curse Israel, has a lengthy and specific process by which he connects with the divine. He requests seven altars, and seven bulls and seven rams to offer up on the altars.
Ibn Ezra’s Teaching
שבעה מזבחות. יש סודות עמוקים לא יבינום כי אם מתי מספר ושביעי בימים ובחדשים ובשנים ושבעה כבשי העולה ושבעה הזאות גם אמר השם לאיוב קחו לכם שבעה פרים ושבעה אילים ובתת שלם לשלם אז תתחדש רוח בינה והמשכיל יבין
Numbers 23:1 SEVEN ALTARS. There are deep secrets which only a few can fathom. The number seven occurs with regard to days (Shabbat), months (Rosh Hashanah begins the seventh month), years (the sabbatical and jubilee years); the seven lambs offered for a burnt offering; the seven sprinklings. God also told Job, take unto you seven bulls and seven rams (Job 42:8).
When the complete is added to the complete, then a spirit of understanding is newly created. The intelligent will understand what I speak of. (Translation adapted from Strickman and Silver)
Reflections for the Path
Seven symbolizes completion in the biblical tradition, most clearly in the creation story, where seven full days account for the entirety of the cosmos. When multiples of seven are used in prophetic rituals, it allows for the prophet to tap into the prophetic inspiration, or as Ibn Ezra describes it, titchadash ruach bina, a spirit of understanding is newly created. Wholeness and newness intertwine, resulting in a rare moment of inspiration.