The scope of the appearance of the risen Jesus given in the gospel extract from Saint Luke today is very great.
The full setting of his teaching was not explicitly evident in the missioning of his earthly life; he was the Galilean who had appeared with gifts of healing which entailed their divine endowment with which some passages in the later part of Isaiah's prophesy anticipated. His doctrinal and moral teaching were the elements of a divine wisdom implicit in all of his words. He claimed a heavenly origin, and that his teaching was implicitly and historically related to the Jewish scriptures, which it fulfilled by clarifying and fulfilling.
The central part of his teaching would be recorded in the discourses and discussions recorded by his disciple Saint John giving the weight of divinity behind his teaching, ultimately to be explained by his unity and identity with the Father, identified with the God of Israel, with whom he will send the Holy Spirit.
In his mission he had spoken as a man, but united personally with the Godhead and accompanied by the presence of Father and Holy Spirit, as also by the angels who had always been with him: anouncing his birth in Bethlehem, and accompanying his solitude in the Judean desert.
After his already prophesied betrayel and arrest, his passion and his Crucifixion by the Roman procurator under the pressure of the Jewish authorities, we are following his appearances in his human body resurrected by his fully-shared Trinitarian divinity. He had, according to Saint Luke, attached himself to two travelling disciples on the way to Emmaus, to whom he had opened the Scriptural perspectives which set him out as recapitulating all Jewish history in the world perspective anounced by the prophet Isaiah.
The disciples had returned immediately to the Apostles in Jerusalem and were telling them of their experience, and at that moment He Himself appeared in their midst uttering the words, 'Peace be with you!' So he called on them to enter into the peaceful heart of his Godhead: to experience its presence which underlay his passion-wounded body. And he asked for food to show that his presence was both physical and spiritual.
In his earthly mission he had spoken as a man; at this moment he speaks from his Godhead through his glorified manhood before its definitive Ascension. So he speaks from the perspective which embraces all perspectives, and therefore with the greatest authority, most useful for their ministering to his body which they would participate as his Church until time's end. He showed them how he was fulfilling prophesies in the Law of Moses, the Prophets and the Psalms.
Exegetes currently identify five Messianic prophesies in the Law-books. Firstly the enmity prophesied betwen the seed of the serpent and the Seed of the woman, not designated by a father (Gen 3,15). Secondly, the blessing promised to all the nations through the Seed of Abraham (Gen 22,18); so Mary is given a priority for the Seed of them both. Thirdly, that 'the [Kingly] sceptre shall not depart from Judah ... until the Conciliator shall come, gathering the people' (Gen 49,10), and here the slain and risen King addresses the Apostles to whom the gathering of all peoples is entrusted.
Fourthly, the princes of neighbouring people of Moab had asked a pagan seer, Baalam, to curse the Israelites, but the inspiration of God compelled him to say 'I shall see him, but not now: ... there shall come a Star out of Jacob, and a Sceptre shall rise out of Israel, and shall smite the corners of Moab' (Num 24,17). Fifthly, 'I will raise up a Prophet from among their brethren and will put my words in his mouth; and he shall speak unto them all that I shall command Him', which is in Deuteronomy (18,18).
This gave the possibility of relating the Law to the highest Wisdom: not just to the Torah existing 'from the beginning' as the Rabbis taught, but a timeless, spiritually uttered Word of God such as he was now giving, to be given by John in his Prologue, and by Matthew in his Sermon on the Mount. Amen.