Now among those who went up to worship at the feast were some Greeks.
 So these came to Philip, who was from Beth-sa'ida in Galilee, and said to him, "Sir, we wish to see Jesus."
 Philip went and told Andrew; Andrew went with Philip and they told Jesus.
 And Jesus answered them, "The hour has come for the Son of man to be glorified.
 Truly, truly, I say to you, unless a grain of wheat falls into the earth and dies, it remains alone; but if it dies, it bears much fruit.
 He who loves his life loses it, and he who hates his life in this world will keep it for eternal life.
 If any one serves me, he must follow me; and where I am, there shall my servant be also; if any one serves me, the Father will honor him.
 "Now is my soul troubled. And what shall I say? `Father, save me from this hour'? No, for this purpose I have come to this hour.
The Greeks were curious gawkers, gentiles who wished to study rather than follow. Christ's response to their request to meet him was to describe how he would truly engage the gentile world: through the Bread of Life offered to all in the Eucharist. It is His sacrifice that becomes the source of salvation for the Jews (who had the scriptural and covenantal understanding) and for the gentiles to whom the Word of God was proclaimed after it had been fulfilled.
Here is B-16's take on this Gospel passage:
Pope Benedict XVI
General audience of 14/06/06 (©Libreria editrice Vaticana)
Saint Andrew, apostle of the Greek world
The first striking characteristic of Andrew, brother of Simon Peter, is his
name: it is not Hebrew, as might have been expected, but Greek, indicative
of a certain cultural openness in his family that cannot be ignored… In
Jerusalem, shortly before the Passion, some Greeks had come to the holy
city… to worship the God of Israel at the Passover Feast. Andrew and
Philip, the two Apostles with Greek names, served as interpreters and
mediators of this small group of Greeks with Jesus… Jesus said to the two
disciples and, through them, to the Greek world: "The hour has come for
the Son of man to be glorified. I solemnly assure you, unless a grain of
wheat falls to the earth and dies, it remains just a grain of wheat; but if
it dies, it produces much fruit" (Jn12, 23-24). What do these words mean in
this context? Jesus wants to say: Yes, my meeting with the Greeks will
take place, but not as a simple, brief conversation between myself and a
few others, motivated above all by curiosity. The hour of my glorification
will come with my death, which can be compared with the falling into the
earth of a grain of wheat. My death on the Cross will bring forth great
fruitfulness: in the Resurrection the "dead grain of wheat" - a symbol of
myself crucified - will become the bread of life for the world; it will be
a light for peoples and cultures…In other words, Jesus was prophesying
about the Church of the Greeks, the Church of the pagans, the Church of the
world, as a fruit of his Pasch. Some very ancient traditions see in Andrew…
the Apostle to the Greeks in the years subsequent to Pentecost. They enable
us to know that for the rest of his life he was the preacher and
interpreter of Jesus for the Greek world. Peter, his brother, travelled
from Jerusalem through Antioch and reached Rome to exercise his universal
mission; Andrew, instead, was the Apostle of the Greek world. So it is that
in life and in death they appear as true brothers - a brotherhood that is
symbolically expressed in the special reciprocal relations of the Sees of
Rome and Constantinople, which are truly Sister Churches.