Revelation 1:4

John sends greetings to the seven Churches in the province of Asia. May grace be granted to you, and peace, from Him who is and was and evermore will be; and from the seven Spirits which are before His throne;

Revelation 1:20

the secret meaning of the seven stars which you have seen in My right hand, and of the seven lampstands of gold. The seven stars are the ministers of the seven Churches, and the seven lampstands are the seven Churches.

Revelation 5:1

And I saw lying in the right hand of Him who sat on the throne a book written on both sides and closely sealed with seven seals.

Revelation 5:6

Then, midway between the throne and the four living creatures, I saw a Lamb standing among the Elders. He looked as if He had been offered in sacrifice, and He had seven horns and seven eyes. The last-named are the seven Spirits of God, and have been sent far and wide into all the earth.

Revelation 8:2

Then I saw the seven angels who are in the presence of God, and seven trumpets were given to them.

Revelation 8:6

Then the seven angels who had the seven trumpets made preparations for blowing them.

Revelation 10:3

he cried out in a loud voice which resembled the roar of a lion. And when he had cried out, each of the seven peals of thunder uttered its own message.

Revelation 15:1

Then I saw another marvel in Heaven, great and wonderful--there were seven angels bringing seven plagues. These are the last plagues, because in them God's anger has found full expression.

Revelation 15:7

And one of the four living creatures gave the seven angels seven bowls of gold, full of the anger of God who lives until the Ages of the Ages.

Revelation 16:1

Then I heard a loud voice from the sanctuary say to the seven angels, "Go and pour on to the earth the seven bowls of the anger of God."

Treasury of Scripture Knowledge

Summary

And seven priests shall bear before the ark seven trumpets of rams' horns: and the seventh day ye shall compass the city seven times, and the priests shall blow with the trumpets.

Bible References

Seven times

Revelation 1:4
John sends greetings to the seven Churches in the province of Asia. May grace be granted to you, and peace, from Him who is and was and evermore will be; and from the seven Spirits which are before His throne;
Revelation 5:1
And I saw lying in the right hand of Him who sat on the throne a book written on both sides and closely sealed with seven seals.
Revelation 8:2
Then I saw the seven angels who are in the presence of God, and seven trumpets were given to them.
Revelation 10:3
he cried out in a loud voice which resembled the roar of a lion. And when he had cried out, each of the seven peals of thunder uttered its own message.
Revelation 15:1
Then I saw another marvel in Heaven, great and wonderful--there were seven angels bringing seven plagues. These are the last plagues, because in them God's anger has found full expression.
Revelation 16:1
Then I heard a loud voice from the sanctuary say to the seven angels, "Go and pour on to the earth the seven bowls of the anger of God."