Revelation 14:1-2

And I saw, and behold, the Lamb standing on the mount Zion, and with him a hundred and forty and four thousand, having his name, and the name of his Father, written on their foreheads. And I heard a voice from heaven, as the voice of many waters, and as the voice of a great thunder: and the voice which I heard was as the voice of harpers harping with their harps