The first sentence
"In the beginning God created heaven and earth."
Genesis 1:1
In Hebrew, that sentence is seven words long:
בְּרֵאשִׁית בָּרָא אֱלֹהִים אֵת הַשָּׁמַיִם וְאֵת הָאָרֶץ
Seven words. Twenty-eight letters, which is 4 times 7.
The Bible's opening line is built on seven before it says anything else.
The seventh day
Then God makes the world in six days, and on the seventh he rests:
"And on the seventh day God ended his work which he had made: and he rested on the seventh day from all his work which he had done. And he blessed the seventh day, and sanctified it."
Genesis 2:2 to 3
Seven is the number of a finished work. Complete. Nothing missing.
Seven, everywhere
Once you see it, it's in every part of the Bible.
Jericho is a good example. "On the seventh day the priests shall take the seven trumpets... and you shall go about the city seven times" (Josue 6:4). Seven, seven, seven. And the walls came down.
Jesus and seven
Peter thought he was being generous when he asked if he should forgive his brother seven times. Jesus answered: "I say not to thee, till seven times; but till seventy times seven" (Matthew 18:22). Completeness, without limit.
In the Gospel of John, Jesus gives seven "I am" sayings. From the cross, he speaks seven times.
The last book
The Bible's final book, Revelation, is built around seven:
"The seven candlesticks are the seven churches" (Apocalypse 1:20). A book "sealed with seven seals" (5:1). "Seven Angels... and to them were given seven trumpets" (8:2). "Go, and pour out the seven vials of the wrath of God" (16:1).
Why this is a big deal
The Bible was written by around forty authors over about 1,500 years. Seven is in its first sentence, its first week and its last book.
The work is finished, and the number seven is its signature.