What does 'instituted by Christ' mean?

Answer 1

You are probably referring to certain practices that have been 'instituted by Christ' - in other words, 'set up' or 'established' by him. The most important is that of Holy Communion (also called 'The Lord's Supper', 'Eucharist' or 'Mass' depending upon the type of church you attend.

The last supper Jesus had with his disciples was at the feast of the Passover; it commemorated the deliverance of the Jewish nation out of Egypt centuries before and thanked God for his Covenant with the people (covenant means 'binding agreement'). However at THIS Passover meal, instead of saying the normal Jewish prayers of Thanksgiving for the old covenant, Jesus took the bread and said to the disciples 'this is my Body' and at the passing round of the wine 'this is my blood' - as a sign of a NEW Covenant between God and his people - not just Jews but all who accept Jesus Christ as their Saviour. By doing this Jesus, as God the Son, was declaring that his life would be sacrificed - in the same way as animals were sacrificed at the old Covenant - but that his sacrifice would be a once-and-for-all sacrifice. By his blood and broken body we would now be reconciled to God. That is why, for a Christian, the death and resurrection of Jesus is central to their faith - that Jesus as God made this NEW covenant with humanity.

Therefore in churches everywhere, we commemorate this occasion in the mass or Holy Communion. We regard this practice as being instituted by Jesus as a sacrament - an earthly and normal practice with a spiritual and heavenly meaning.