Seven was symbolic in ancient near eastern and Israelite culture and literature. It communicated a sense of fullness or completeness ( seven is spelled with the same consonants as the word complete/full ). This makes sense of the pervasive appearance of seven patterns in the Bible.
In some religions, such as Christianity and Judaism, 7 is seen as a number of completion and perfection. In ancient times, the number 7 was associated with the seven visible celestial bodies: the Sun, the Moon, Mars, Mercury, Jupiter, Venus, and Saturn.