Why is there an extra candle at the altar when a bishop celebrates the liturgy?

Why is there an extra candle at the altar when a bishop celebrates the liturgy?

You may notice when a bishop celebrates the liturgy there is an extra candle placed on or near the altar. There is a theological reason behind this extra candlestick. According to the General Instructions on the Roman Missal (GIRM),“…on or next to altar are be placed candlesticks with lighted candles: at least two in any celebration, or even four or six, especially for Sunday Mass or a Holy Day of Obligation, or if the Diocesan Bishop celebrates, then seven candlesticks with lighted candles (117). We find in the Book of Revelations, which is a description of celestial liturgy, “…and before the throne were burning seven torches of fire, which are the seven spirits of God.” (Rev 4:5).The number seven was symbolic of Israelite culture in that is communicated a sense ‘fullness’ or ‘completeness’. If we look at the Hebrew word for ‘seven’ (שבע) it is spelled with the same consonants as the word for ‘complete/full’ (שבע). In relation to the bishop, he has the ‘fullness’ of the priesthood of Christ. In relation to ‘completeness’, when the bishop celebrates the liturgy, it manifests the mystery of the Church of all God’s holy people. (cf. Ceremonial of Bishops, 11-12).Nevertheless, it is important to realise that the number of candles does not signify a more efficacious or better celebration of the Mass, but reflects the gradation of festival days and persons involved.