‘And I saw as it were a glassy sea mingled with fire, and those who came victorious from the beast, and from his image, and from the number of his name, standing by the glassy sea, having harps of God.'
Here John is looking forward to the rapture and resurrection. He is declaring that what is to follow need not disturb God's people for their future is secure. Whether it be persecution at the hands of Roman emperors, or persecution by others who are like-minded, they may know that when it has been accomplished they will be able to put their seal of approval on what God has done. The solid glassy sea reminds us that for them daily washing from earthliness is no longer required. Thus the water of the sea is solidified (see on Revelation 4:6). It is pure glass referring to the holiness which the people of God now enjoy (see Revelation 21:18; Revelation 21:21). It is seen as mingled with fire another symbol of holiness (Revelation 1:14; Revelation 3:18 compare Mark 9:49). Now they are in Heaven His people no longer need the water of washing nor the fire for refining.
The sea of fire can also be seen as in direct contrast with the lake of fire, the destructive fire which destroys the wicked (Revelation 19:20), the one refers to eternal joy and bliss, the other to eternal judgment and destruction. They represent two aspects of the holiness of God. The one represent the joy of holiness received and enjoyed in the presence of God. The second the response of holiness to the sinfulness of the unrepentant.
Those who are overcomers, overcoming the claims of the world beast and not entangled in his snares, are there with harps of God in their hands. Harps speak of worship (Revelation 5:8; Psalms 33:2; Psalms 43:4 and often), and joy (Isaiah 24:8) and victory (Revelation 14:2). That they are harps of God demonstrates a gift of special affection. They are His gifts. Their rewards have begun.