Irenaeus criticizes the heretics on the grounds that they have "disregarded the order and connection of the Scriptures." They have, he charges, rearranged the members of the body of truth, much as do those who take a mosaic of a king and rearrange the stones to form a picture of a dog or fox, claiming that this is the original picture. Those who know the "canon of truth," delivered in baptism, will be able to restore the passages to their proper order, so revealing the image of the King.
The "canon of truth" functions very much like the "pattern of sound words" to which Paul urged Timothy to hold firm (2 Tim. 1:13). By holding to this canon, Christians can proclaim in a continually changing context the same gospel—the "tradition" preserved in the Church.
In this way, Christ is, for Irenaeus, the subject of Scripture throughout. The apostles proclaimed him by reference to the Scriptures. The prophets saw "the Son of God as man conversing with men; they prophesied what was to happen … declaring that the one in the heavens had descended into the 'dust of death'" (Ps. 21.16; Septuagint). Christ was not yet present, but his saving Passion was already the subject of the prophets' words and visions.
Jesus wrote it all
Not only is Jesus Christ the subject of Scripture, from beginning to end, but he is also its ultimate author: Irenaeus takes Jesus' statement that "Moses wrote of me" (John 5.46) to mean, "the writings of Moses are his words," and then extends this to include "the words of the other prophets." So, Irenaeus urges Marcion, "read with earnest care that Gospel which has been given to us by the apostles, and read with earnest care the prophets, and you will find that the whole conduct, and all the doctrine and all the sufferings of our Lord, were predicted through them."
"If anyone reads the Scriptures in this way," Irenaeus argues, "he will find in them the Word concerning Christ and a foreshadowing of the new calling." Using Christ's image of a treasure hidden in a field (Matt. 13:44), where the disciples are sent to reap what others have sown ( John 4:35-8 ), Irenaeus suggests that Christ himself is the treasure, hidden in Scripture, in the types and parables, the words and actions of the patriarchs and prophets, which prefigure what was to happen in and through Christ in his human advent as contained in the Gospel. By their writings, the patriarchs and prophets have prepared the world for the advent of Christ, so that the field is ready for harvest.
Before their consummation in the Christ's advent, these types and prophecies could not be understood. But the cross now sheds light on these writings, revealing what they in fact mean and how they are thus the Word of God. For those who read Scripture without knowing the "explanation" (literally "exegesis") of those things pertaining to Christ, the Scriptures remain only fables. However, those who read Scripture with understanding will be illumined and shine as the stars of heaven.
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