However his spirit could enter because of the righteousness of Jesus Christ and the cleansing or purifying of his sins. John was unable to describe any shape or form. All he could do was to speak of diamond brilliance and the fiery red presence that glowed, the glory of God. A rainbow was around the throne that was bright, shiny, and emerald green in color. Rainbow is the symbol of covenant or promise given by God.
Elder is the same as pastor or bishop.
The number 24 occurs 6 times in the Old Testament. In every case, it is associated with the priests of Israel. On occasion, the entire nation of Israel was represented by the 24 priests. Just as the 24 priests represented all of Israel, the 24 elders will one day represent all believers from Pentecost to the Rapture. Just as the elders were dressed in white, in heaven we will all be clothed in white representing the righteousness of Jesus Christ.