Luke is unique of the four gospels in depicting a trial scene between Jesus and King Herod. The same account is also missing in the Acts of Pilate and other apocryphal gospels and is thus probably a Lukan composition. As Crossan, Koester, Helms, and others have shown, the Passion narratives are almost entirely constructed of material stitched together through OT exegesis. Sometimes the source texts are made explicit through quotation, and other times they lie behind the surface -- detectable through allusion, paraphrase, and wording. The Lukan narrative of Jesus' hearing before Herod was inspired by OT statements but nowhere are the source texts directly mentioned:
"When he learned that Jesus was under Herod's jurisdiction, he sent him to Herod, who was also in Jerusalem at that time. When Herod saw Jesus, he was greatly pleased, because for a long time he had been wanting to see him. From what he had heard about him, he hoped to see him perform some miracle. He plied him with many questions, but Jesus gave him no answer. The chief priests and the teachers of the law were standing there, vehemently accusing him. Then Herod and his soldiers ridiculed and mocked him. Dressing him in an elegant robe, they sent him back to Pilate. That day Herod and Pilate became friends -- before this they had been enemies." (Luke 23:7-12)
Luke's narrative is largely borrowed from the earlier scenes between Jesus and Pilate (cf. 23:1-6) and the high priests (22:66-71), but no scriptural reason is given for the meeting between Herod and Jesus. It is clear that an older exegetical tradition lay behind this story but Luke gives no hint of it. There were other second century writers, however, who still had access to the exegetical tradition and alluded to it in their descriptions of Jesus' hearing before Herod. Justin Martyr (c. 150 A.D.) wrote: "And when Herod succeeded Archelaus, having received the authority which had been allotted to him, Pilate sent to him by way of compliment Jesus bound; and God foreknowing that this would happen, had thus spoken: 'And they brought him to the Assyrians, a present to the king' " (Dial. Trypho, 103). The scripture that Justin uses to build his mini-story is Hosea 10:6. The exegetical tradition that lay behind Justin's story was thus one that construed Jesus as a present to the king (technically, Herod was not king but tetrarch). Justin historicizes this gesture of gift-giving with Herod's accession to the seat of Archelaus. This is clearly an independent tradition to that in Luke, which does not depict Jesus as a "gift" and which characterizes Pilate's sending of Jesus to Herod as a matter of jurisdictional protocal (instead of being a congratuatory compliment). Moreover, Pilate is presented as entirely congenial to Herod, while Luke designates the two of them at the time as "enemies". Justin's story is unhistorical because Herod Antipas ascended the throne as tetrarch at the same time as his brother Archelaus and thus never succeeded him; in reality, Archelaus was followed by the procurators Gratus and Pontius Pilate. Justin may have thus been thinking of Herod Agrippa, who took power in A.D. 37 and the first since Archelaus to successfully bear the title "king". There is one final detail in Justin's account that is independent to Luke: the description of Jesus as "bound". Although Justin omits this word from the quotation, Hosea 10:6 (LXX) does describe the prisoner as "bound" (e.g. "And having bound it for the Assyrians, they carried it away as presents to king Jarim").
Irenaeus (c. A.D. 180) gives a lengthier and more explicit account:
"And again David says thus concerning the sufferings of Christ: 'Why did the Gentiles rage, and the people imagine vain things? Kings rose up on the earth, and princes were gathered together against the Lord and his Anointed.' For Herod the king of the Jews and Pontius Pilate, the governor of Claudius Caesar, came together and condemned him to be crucified. For Herod feared, as though he were to be an earthly king, lest he should be expelled by him from his kingdom. But Pilate was constrained by Herod and the Jews that were with him against his will to deliver him to death, for they threatened him if he should not rather do this than act contrary to Caesar, by letting go a man who was called a king.... Again he says in the Twelve Prophets, 'And they bound him and brought him as a present to the king.' For Pontius Pilate was governor of Judaea, and he had at that time resentful enmity against Herod the king of the Jews. But then, when Christ was brought to him bound, Pilate sent him to Herod, giving command to enquire of him, that he might know of a certainty what he should desire concerning him; making Christ a convenient occasion for reconciliation with the king." (Irenaeus, Demonstration of the Apostolic Preaching 74, 77)
The two scriptures forming the basis of this account are Psalm 2:2 and Hosea 10:6. Irenaeus' account resembles that of Justin Martyr to some extent; it cites Hosea and refers to Jesus being bound. But it rejects (or has no knowledge of) the historical setting Justin mentions, namely the accession of Herod as the successor of his brother Archelaus. It also shares one important theme with Luke: that Pilate and Herod had been on ill terms and the incident with Jesus help reconcile their differences. It also depicts the inquisition of Jesus by Herod. But the Irenaeus version lacks several distinctive themes from Luke: Herod's interest in seeing Jesus perform a miracle, Herod's mocking of Jesus, the elegant robe. Luke also presents Herod as delighted with Jesus, while Irenaeus describes him as feeling threatened by his Messianic claims. So while Irenaeus combines themes found in both Luke and Justin, it seems quite possible that his account was an independent formulation from the exegetical tradition. This seems to be confirmed by Irenaeus' emphasis on Herod's fear of Jesus' kingship, which parallels that of Herod the Great in the navitity story of Matthew; Luke has no such story about Herod. Thus, we have here an interesting example of storytelling about Jesus that drew heavily on both oral tradition and the interpretation of OT passages which are mined for motifs to add to the growing tradition about Jesus' life and Passion.