In the days of ancient Israel, the Tabernacle was the earthly dwelling of God, where the Ark of the Covenant was housed. Therefore, the ancient Tabernacle prefigures the tabernacles used today in Orthodox worship.
In early Christianity, presbyters and even lay people took bread consecrated at Eucharistic celebrations to their homes in order to give it to the sick and others unable to attend the celebration. But when the Edict of Milan ended persecution, the practice was established of keeping the Eucharist only in churches and no longer in people's homes. Later as liturgical implements became more specialized, the tabernacle was made as a permananent vessel for the Eucharist.
In the Orthodox Church, the reserve sacrament is kept in the tabernacle on the altar at all times. The tabernacle is usually elaborately decorated, normally wrought with gold, silver, or wood and precious adornments. The tabernacle is often shaped like a miniature church building. Every year on Holy Thursday, the priest consumes whatever is left of the reserve sacrament and places some of the sacrament left over from the Holy Thursday Divine Liturgy into the tabernacle. The presence of Christ in the tabernacle is always indicated by a vigil lamp, burning perpetually.