Pyrophilia or fire worship is a pagan practice and ideally has no place in Christianity. There are few biblical references which would support such a practice. one must distinguish between Light- which takes various forms, and Fire, usually at the very least potentially destructive. Okay one has candles in churches, but nowadays these are being phased out with time-controlled flickering strobe lights made to look like candles, Fire Hazard, you know. I have never heard of Holy Fire Saturday. Candles have various religious applications, as suggested above- there was a Candlemas that tied in with Ground Hog day. ( Candles were blessed on this day). Pentecost doe sinvolve the ( tongues of fire) of the Holy Spirit, but not in any worship sense- there are no torchlights, etc. In a sense the Spirit was broadcast to all the faithful in the unnamed Upper Room. I have never heard of Holy Fire Saturday. Pentecost is always celebrated on sundays- hence the name Whitsunday- or White Sunday- Confirmation used to be performed on this Church Holiday., which is tied into Easter and hence movable but usually in May.