Why is the number 7 significant?

[CyrilSebastian]

Why is the number 7 significant in the Bible?

[Benedict]

Why is the number 7 significant in the Bible?

The number 7 is the highest single digit prime number and symbolizes perfection and fulfillment. God rested on the seventh day and hallowed it.
The clean animals brought into the ark by 7s.
7 lamb's stood as witness to Abraham and Abimelech.
Jacob labored 7 years for each wife.
Jacob bowed himself to the ground 7 times before Esau.
Joseph saw 7 cows and 7 stalks of grain. This signified 7 years of plenty.
The 7 unhealthy cows and 7 unhealthy stalks of grain signifying 7 years of famine.
Midian had 7 daughters.
7 days of Passover eating unleavened bread.
7 lamps on the menorah symbolizes  the seven heavens and the seven spirits of God.
 The blood was sprinkled 7 times upon the veil.
The altar and the utensils and the laver and the base were sprinkled with anointing oil 7 times to consecrate them.
Persons who were sick were checked on every 7 days to see signs of improvement.
The leper is sprinkled 7 times with blood from a bird.
Those who were to have atonement offered for them the priest would sprinkle oil 7 times before God.
The mercy seat was sprinkled with the blood of bulls 7 times.
The horns of the altar were cleansed of sin by sprinkling blood 7 times of sheeps and goats.
In the Law the Lord would punish those who refused to admit 7 fold for their sins.
7 fold plagues were given to those under the Law who refused go obey God.
The priests carried 7 trumpets when they walked around Jericho for 7 days.
7 priests bore trumpets before the ark.
Elisha raised to life a boy who then sneezed 7 times.
Elisha had Naaman dip the in Jordan 7 times to cure his leprosy.

[CyrilSebastian]

King David referenced the number seven in describing the perfect nature of God's words   
when he wrote that the Lord's words are flawless, "like gold refined seven times".

[CyrilSebastian]

In the context of perfection, Jesus spoke in a grouping of seven when he was asked how we should pray.   
 The Gospel According to St. Matthew Chapter 6: Verses 9-13

[Benedict]

Saint Vicente On the Creation of the World
"Behold the seven horns of the Lamb, [ Revelation 5:6 ] the seven eyes of God [ Zechariah 4:10 ] — the seven eyes are the seven spirits of the Lamb; [ Revelation 4:5 ] seven torches burning before the throne of God [ Revelation 4:5 ] seven golden candlesticks, [ Revelation 1:13 ] seven young sheep, [ Leviticus 23:18 ] the seven women in Isaiah, [ Isaiah 4:1 ] the seven churches in Paul, seven deacons, [ Acts 6:3 ] seven angels, seven trumpets, seven seals to the book, seven periods of seven days with which Pentecost is completed, the seven weeks in Daniel, also the forty-three weeks in Daniel; with Noah, seven of all clean things in the ark; seven revenges of Cain, [ Genesis 4:15 ] seven years for a debt to be acquitted, [ Deuteronomy 15:1 ] the lamp with seven orifices, [ Zechariah 4:2 ] seven pillars of wisdom in the house of Solomon. [ Proverbs 11:1 ] Now, therefore, you may see that it is being told you of the unerring glory of God in providence; yet, as far as my small capacity shall be able, I will endeavour to set it forth. That He might re-create that Adam by means of the week, and bring aid to His entire creation, was accomplished by the nativity of His Son Jesus Christ our Lord. Who, then, that is taught in the law of God, who that is filled with the Holy Spirit, does not see in his heart, that on the same day on which the dragon seduced Eve, the angel Gabriel brought the glad tidings to the Virgin Mary; that on the same day the Holy Spirit overflowed the Virgin Mary, on which He made light; that on that day He was incarnate in flesh, in which He made the land and water; that on the same day He was put to the breast, on which He made the stars; that on the same day He was circumcised, on which the land and water brought forth their offspring; that on the same day He was incarnated, on which He formed man out of the ground; that on the same day Christ was born, on which He formed man; that on that day He suffered, on which Adam fell; that on the same day He rose again from the dead, on which He created light? He, moreover, consummates His humanity in the number seven: of His nativity, His infancy, His boyhood, His youth, His young-manhood, His mature age, His death. I have also set forth His humanity to the Jews in these manners: since He is hungry, is thirsty; since He gave food and drink; since He walks, and retired; since He slept upon a pillow; [ Mark 4:38 ] since, moreover, He walks upon the stormy seas with His feet, He commands the winds, He cures the sick and restores the lame, He raises the blind by His speech, — see that He declares Himself to them to be the Lord."

[CyrilSebastian]

The Lord's Prayer contains seven petitions.

[CyrilSebastian]

Israelites failed to observe 70 Sabbath years, hence the 70 years in captivity.

[CyrilSebastian]

Deuteronomy mentions that on every seventh year, the Israelites were to cancel debts they had   
made with each other and free their slaves.