Polycrates of Ephesus, a notable bishop of the time, was a contemporary of Melito, and in one of the letters preserved by Eusebius, Polycrates describes Melito as having fully lived in the Spirit. Jewish by birth, Melito lived in an atmosphere where the type of Christianity practiced was largely oriented toward the Jewish form of the Christian faith. Coming out of and representing the Johannine tradition, Melito's theological understanding of Christ often mirrored that of John. However, like most of his contemporaries, Melito was fully immersed in Greek culture. This Johannine tradition led Melito to consider the Gospel of John as the chronological timeline of Jesus’s life and death. This in turn led to Melito’s standpoint on the proper date of Easter discussed in Peri Pascha which he held as the 14th of Nisan.
Formerly the capital of the Lydian Empire, Sardis underwent a process of Hellenization due to the influence of Alexander the Great, thus making Sardis a thoroughly Greek city long before Melito was born. Trained in the art of rhetorical argumentation, Melito is believed to have been greatly influenced by two Stoic philosophers in particular, namely, Cleanthes and Poseidonius. Also proficient in the allegorical interpretation of Homer due to being schooled by sophists, it is highly likely that his background in Stoicism fed into how he wrote and how he interpreted past events and figures of religious significance such as Moses and the Exodus. Both his Jewish background and background in Stoicism led to his beliefs that the Christian Passover, celebrated during Easter, should be celebrated at the same time as the Jewish Passover. His belief in the Old Covenant being fulfilled in Jesus Christ also led to his opinion of the date of Easter.
Written during the second century C.E., and only coming to light within the modern world due to the efforts of Campbell Bonner in 1940, some have argued that Peri Pascha is not a homily, but is based on a haggadah, which is a retelling of the works of God at Passover. The Quartodeciman celebration mainly being a commemoration of Christ's passion and death, Melito stood by the belief that Christ died on the evening of the 14th, when the Passover meal was being prepared. F.L. Cross states that Melito’s treatise on Pascha is “the most important addition to Patristic literature in the present century”. The Peri Pascha provides an accurate description of Christian feelings towards Jews at the time and their opinion of Judaism. The text is not an all-out attack on the Jewish people; however, the Jewish people are blamed for the immortal Christ being killed by mortals. Melito does not blame Pontius Pilate for the crucifixion of Jesus Christ.
Aside from the liturgical function of the Peri Pascha, this early Christian document has traditionally been perceived as a somewhat reliable indicator concerning how early Christians felt toward Judaism in general. This text blames the Jews for allowing King Herod and Caiaphas to execute Jesus. However, the goal was not to incite anti-Semitic thoughts in Christians but to bring light to what truly happened during the Passion of Jesus Christ. In part a response to the affluence and prestige of the Jewish community of Sardis, Melito may have been fueled by a desire for Christians. Another consideration to take note of is that perhaps Melito was in a competition with the local Jewish community for pagan converts. Wanting to differentiate the Christian community from the Jewish one since the two were very similar, it was more a matter of strengthening the Christian sense of distinctiveness than an all out attack on the local Jews of Sardis. Thus, Melito is widely remembered for his supersessionism. This view basically assumes that the Old Covenant is fulfilled in the person of Jesus Christ. This view of supersessionism also assumes that the Jewish people fail to fulfill the Old Covenant due to their lack of belief in Jesus Christ.
Attracting the attention of persons such as Epiphanius, Chrysostom, and Pseudo-Hippolytus, Quartodeciman practices have encouraged many to deeply ponder questions pertaining to the duration of the period of fasting, and when it should end within the celebration of any Christian Passover. Another question which bothered many individuals was whether everyone ought to uniformly observe Easter on the same day. Melito thought that the Christian Passover should be on the 14th of Nisan, but the Council of Nicaea determined that Jesus Christ's resurrection from the dead should always be celebrated on a Sunday. Uniformity in church practice was thus the primary drive behind this initiative. Known for following a Johannine chronology, and for believing in a paschal lamb typology, Quartodeciman thought is constituted as such. One of the issues raised is that Quartodeciman thought is the idea that Christian Passover would be celebrated at the same time as Jewish Passover. Ultimately the Council of Nicea decided otherwise and agreed that it would always be on a Sunday.
During the controversy in Laodicea over the observance of Easter, Melito presented an Apology for Christianity to Marcus Aurelius, according to Eusebius, in his Chronicon, during the years A.D. 169-170. A Syriac translation of this apology was rediscovered and placed in a British museum where it was translated into English by Cureton. In this apology, Melito describes Christianity as a philosophy that had originated among the barbarians, but had attained to a flourishing status under the Roman Empire. Melito asks the emperor to rethink the accusations against the Christians and to renounce the edict against them. Melito argues that Christianity had in no way weakened the empire which continued to grow despite the presence of Christianity. Complaining about how the godly are being persecuted and harassed by new decrees, Christians are openly robbed and plundered by those who are taking advantage of the said ordinances. The suffering of Christians at the time in regard to these decrees was mostly of property and taxations while not as much physical suffering. Certainly Christians were persecuted physically as well but in terms of the decrees they were openly robbed and considered to be incestuous and take part in ritualistic acts such as eating children. Melito aimed to dispel the suffering of the Christian people and to change the Greek opinion of them. Demonstrating how Christian thought first flourished among the Gentiles, and how it has benefited the empire, Melito tried to convince the emperor to rethink his current policies since Christianity only brought greatness and success to Rome. Reminding the emperor of the virtuous conduct of Hadrian, Melito called for an end to all violence toward the growing Christian communities within the empire.
Emphasizing, like John, the unity of Christ and the Father, Melito declared that Christ is at once God and a perfect man. Having two essences while being one and the same, his godhead was demonstrated by way of all of the signs and miracles he performed after being baptized.Successfully managing to hide his divinity from the world before that central event occurred with John the Baptist, Jesus felt the pangs of hunger just like everyone else. Writing against Marcion, Melito focused on Christ's divinity and humanity in order to counter the claim that Jesus was simply and uniquely divine; having no material counterpart. Melito does not anthropomorphize the divine nature of Christ and keeps the attributes of the divine nature and the human nature wholly separate. While he describes the attributes of each nature separately, he also speaks of the two natures of Christ combined. The form of speech used is that of two natures in one Christ. According to Melito, Jesus Christ was both entirely human and entirely divine.
Melito gave the first Christian list of the canon in the Old Testament. In his canon he excludes the Books of Esther, Nehemiah, and the Apocrypha. Around 170 after traveling to Palestine, and probably visiting the library at Caesarea Maritima, Melito compiled the earliest known Christian canon of the Old Testament, a term he coined. A passage cited by Eusebius contains Melito's famous canon of the Old Testament. Melito presented elaborate parallels between the Old Testament or Old Covenant, which he likened to the form or mold, and the New Testament or New Covenant, which he likened to the truth that broke the mold, in a series of Eklogai, six books of extracts from the Law and the Prophets presaging Christ and the Christian faith. His opinion of the Old Covenant was that it was fulfilled by Christians, whereas the Jewish people failed to fulfill it. The New Covenant is the truth found through Jesus Christ.
In regard to the death of Melito, there is not much information preserved or recorded. Polycrates of Ephesus, in a letter addressed to Pope Victor (AD. 196) preserved in Eusebius’ history, says, “What shall I say of Melito, whose actions' were all guided by the operations of the Holy Spirit? Who was interred at Sardis, where he waits the resurrection and the judgement?". From this it may be inferred that he had died some time previous to the date of this letter at Sardis, which is the place of his interment. Melito's reputation as a writer remained strong into the Middle Ages: numerous works were pseudepigraphically ascribed to him. Melito was especially skilled in the literature of the Old Testament, and was one of the most prolific authors of his time. Eusebius furnished a list of Melito's works. While many of these works are lost, the testimony of the fathers remains to inform us how highly they were viewed. Eusebius presents some fragments of Melito's works and some others are found in the works of different writers. Fragments' of his works found preserved in a Syriac translation are now stored in the library of the British Museum. Cureton has translated some and others have been published in Kitto's Journal of Sacred Literature, vol 15. Due to Melito’s reputation, many works are falsely attributed to him due the lack of recorded literature surrounding him. Melito was a Chiliast, and believed in a Millennial reign of Christ on Earth, and followed Irenaeus in his views. Jerome (Comm. on Ezek. 36 ) and Gennadius (De Dogm. Eccl., Ch. 52) both affirm that he was a decided millennarian and as such believed that Christ would reign for 1000 years before the coming of the final judgement.