Take, for instance, the use of white vestments at a funeral. My immediate answer, in the past, has been that funerals build on the symbolism of Easter -- which is not specific enough.
As many are quick to point out, every Sunday is a "little Easter," so why don't we wear white every Sunday?
So allow me to be more specific:
Every Sunday is in fact a little Easter, the day on which the Church gathers to celebrate Christ's victory over Death and the grave. For this reason, we break our Lenten fast on Sundays. But various Sundays carry different themes -- be it the fire of the Holy Spirit, the blood of the martyrs, penitence, or God's victorious reign. The color of the vestments aids in communicating these themes -- which is exactly why liturgy nerds have drawn-out debates over the use of purple or blue vestments and paraments during Advent.
In the Church, we use white and gold to express Christ's triumphant glory on major feast days -- at the Incarnation, the Baptism of Our Lord, the Transfiguration, and throughout the entire fifty days of Easter.
At funerals, we hope in the Resurrection -- the ultimate display of God's glory -- and so we use white vestments. Even during Lent, when the Church dawns a penitential purple, puts a hold on weddings and baptisms, and fasts for forty days, we still don white for funerals. The hope of the Resurrection bursts through the Lenten season.
It's the same reason that we light the Paschal Candle at funerals and during the Sacrament of Holy Baptism. And, much like the Paschal Candle, some may reply by asking, "Well, if the theme is Resurrection, why not wear white every Sunday? Isn't every Sunday a little Easter?" In response, I refer you to my summary of Bp. Alexander's discussion of this point (found in full here):
[W]hile every Sunday is a "little Easter" and that the theology of the Resurrection permeates every Divine Service throughout the year regardless of seasonal and thematic overtones, that we still mark Easter proper with special distinction -- pre-Paschal fasting during Lent, the Triduum, the Vigil, extra acclamations, and the like. These distinctives set Easter apart as a sacred time among sacred times. Some of these markers (in this case, the Paschal candle) carries further into the rest of the year.Just so, wearing white and gold vestments is one of those special distinctions that grabs the attention. It sets apart holy seasons, and to be sure, as we bury departed saints, we call special attention to Our Lord's triumph over the grave. Our funeral services point to Easter even more so than a weekly Service during ordinary time.
Now, of course, all of this can be chocked up to adiaphora. God isn't going to refuse the faithful departed entry into paradise if the altar frontal is green. St. Peter isn't watching through a telescope to ensure that the presbyter is wearing a white and gold stole. But let's not forget that the words we use, the symbols we adopt, the colors we wear do actually communicate something. So while white vestments are in fact non-essential, that does not make them unimportant.
