The ancient (and EF) formulae for Palm Sunday speak of both Palm and Olive branches. Palm, of course, is the ancient Mediterranean symbol of Victory: and our Lord's triumphant ride into Jerusalem is what we might call the pre-emptive procession of the Great Conqueror. Perhaps we should not think of Holy Week in too 'linear' a way. It is well known that S John's Gospel, read in the Western Rite on Good Friday, emphasises the Victory of the Cross (Victory doesn't have to wait for Easter morning). On Maundy Thursday, the Lord gives his disciples to eat and drink the Body and Blood which, in terms of a simplistic 'linear' approach, have not yet been broken, shed, or sacrificed. Yet he gives them to his disciples as already sacrificed. And Triumph is already integral to Palm Sunday. All the themes and elements of Pascha surface in all the rites of Holy Week; it is a thematic unity, even if poor mortals, bogged down by 'linear' time, have to take the components one at a time. The soon-to-be-taxed bag you brought back from the shop contains all your groceries simultaneously, even if you have to take them out one at a time.
Olive has, if anything, an even profounder ideology associated with it than Palm. It suggests richness and fruitfulness enjoyed in peace. The EF prayers referred to the twig which the dove brought back to Noah, emblem of the end of God's wrath, emblem of the first covenantal peace between God and his people. How fitting to meet it on this day when He who is the New Covenant sets aside the Temple Sacrifices by cleansing the Temple of the beasts awaiting immolation so that, antitype for type, he can set up the Eucharistic New Table of Sacrifice for his new people. We meet Olive again at the Chrism Mass, and I would like here to revive an edifying speculation of Dom Gregory Dix. Ancient Jewish tradition held that the tree of life standing in the midst of the garden of Eden was an Olive, from which came the oil of mercy that cured both pain and death. That is why patristic sources insistently associate the Chrism of Confirmation with immortality and resurrection.
There is evidence that for the 'hippolytan' writings, the tree from which this oil flows is the tree of the Cross. It seems to me that here the images of scripture and tradition merge and mingle. The Cross, the New Tree in the New Garden, is the true tree of life, and the Anointing (Chrisma) which makes and marks us as Christians unto everlasting life flows from that tree. And it is the tree of which Venantius Fortunatus in his Pange lingua teaches us that it is itself soaked, anointed, through and through, with the blood of the lamb ( ...quem sacer cruor perunxit fusus agni corpore).
A preChristian Jewish writing pictures Adam begging to be given of the oil that flows from the tree in garden. He is given for anwer: 'It shall not be thine now, but at the end of the times. Then shall all flesh be raised up and God will give them of the tree of life'. Praise be to God, who, here in the end-time, gives us to be marked with the anointing of eternity.