The number 7 means "perfection" or "completeness".
It's interesting then that there are seven blessings in the book of Revelation.
Blessed is he that readeth, and they that hear the words of this prophecy, and keep those things which are written therein: for the time is at hand.
- Revelation 1:3 (KJV)
And I heard a voice from heaven saying unto me, Write, Blessed are the dead which die in the Lord from henceforth: Yea, saith the Spirit, that they may rest from their labours; and their works do follow them.
- Revelation 14:13 (KJV)
Behold, I come as a thief. Blessed is he that watcheth, and keepeth his garments, lest he walk naked, and they see his shame.
- Revelation 16:15 (KJV)
And he saith unto me, Write, Blessed are they which are called unto the marriage supper of the Lamb. And he saith unto me, These are the true sayings of God.
- Revelation 19:9 (KJV)
Blessed and holy is he that hath part in the first resurrection: on such the second death hath no power, but they shall be priests of God and of Christ, and shall reign with him a thousand years.
- Revelation 20:6 (KJV)
Behold, I come quickly: blessed is he that keepeth the sayings of the prophecy of this book.
- Revelation 22:7 (KJV)
Blessed are they that do his commandments, that they may have right to the tree of life, and may enter in through the gates into the city.
- Revelation 22:14 (KJV)