The "Sea of Glass Mixed with Fire" is a vivid and symbolic image found in the Book of Revelation, specifically in Revelation 15:2. This imagery is part of the apocalyptic vision given to the Apostle John, which reveals profound truths about the heavenly realm and the ultimate triumph of God over evil.

Biblical Reference:
Revelation 15:2 states: "And I saw something like a sea of glass mixed with fire, and those who had conquered the beast and its image and the number of its name were standing beside the sea of glass with harps of God in their hands."

Symbolism and Interpretation:

1. Sea of Glass:
The "sea of glass" is a recurring motif in the Book of Revelation, first mentioned in Revelation 4:6, where it is described as being "like crystal" before the throne of God. This imagery suggests purity, tranquility, and the unchanging nature of God's presence. The glass-like sea represents the separation between the divine and the earthly, a barrier that is transparent yet impenetrable, signifying the holiness and majesty of God.

2. Mixed with Fire:
The addition of "fire" to the sea of glass in Revelation 15:2 introduces an element of judgment and purification. Fire in biblical literature often symbolizes God's holiness, judgment, and the refining process. The mixture of fire with the sea of glass may indicate the impending judgment upon the earth and the purifying trials that believers endure. It reflects the dual aspects of God's nature—His mercy and His justice.

3. Conquerors of the Beast:
Those who stand beside the sea of glass mixed with fire are described as having "conquered the beast and its image and the number of its name." This group represents the faithful believers who have overcome the trials and temptations of the world, particularly the oppressive forces symbolized by the beast. Their victory is attributed to their steadfast faith and allegiance to God, even in the face of persecution.

4. Harps of God:
The harps in the hands of the conquerors signify worship and praise. In the context of Revelation, music and singing are often associated with heavenly worship and the celebration of God's redemptive acts. The presence of harps underscores the joy and triumph experienced by those who have remained faithful, as they participate in the heavenly liturgy.

Theological Significance:

The vision of the sea of glass mixed with fire serves as a powerful reminder of the ultimate victory of God and His people over evil. It emphasizes the themes of divine judgment, purification, and the reward for faithfulness. The imagery calls believers to remain steadfast in their faith, assured of their place in the heavenly realm where they will join in eternal worship and celebration of God's glory.

This passage also highlights the tension between the present struggles of the faithful and the future hope of vindication and reward. It encourages believers to persevere, knowing that their trials are temporary and that they will ultimately stand victorious before the throne of God.