What does Revelation 4:6 mean?
This verse refers to a sea of glass as clear as crystal in front of God's throne. In Old Testament worship, Israel's priests had to wash their hands and feet at a bronze basin before approaching God (Exodus 30:18–21). The washing symbolically represented cleansing of the sins of specific deeds and general conduct. Here on earth, the blood of Jesus washes away the sins of all who believe on Jesus as Savior (1 Corinthians 6:10–11; Hebrews 9:13–14; 1 Peter 1:18–19). Having been washed in the blood of Jesus, believers receive cleansing from sins by confessing them.First John 1:9 promises, "If we confess our sins, he is faithful and just to forgive us our sins and to cleanse us from all unrighteousness." In heaven there is no need of cleansing from sin, so no water comes between worshipers and God. The water has become a sea of glass.
John tells us he also saw four living creatures around God's throne. He describes them as having eyes in front and behind. Apparently, they guard God's throne, keeping watch over everything that comes near to His throne.