Eastern Orthodox theologian Alexander Schmemman notes that the cult of the saints, including veneration of saints and relics, was not mediatory or sanctifying. “It was sacramentally eschatalogical. It was “sacramental” in the sense that the presence of Christ attested to by the marty’s exploit was manifested in his body. It was eschatalogical because the martyr by his death demonstrated the power given to him by the Church” (Introduction to Liturgical Theology, p. 187).

But it didn’t stay this way.

The “emphasis” in the cult of saints shifted from the scramentally eschatalogical to the sanctifying and intercessory to meaning of veneration. The remains of the saint, and later even articles belonging to him or having once touched his body, came to be regarded as sacred objects having the effect of communicating their power to those who touched them. Here is the basis of the cult of the saints which appeared in the Church in the fourth century. The early Church treated the relics of the martyrs with great honor–“But there is no indication,” writes Fr Delehaye, “that any special power was ascribed to relics in this era, or that any special, supernatural result would be obtained by touching them. Toward the end of the fourth century, however, there is ample evidence to show that in the eyes of believers some special power flowed from the relics themselves.” (p. 189)

So for the Eastern Orthodox, it doesn’t have to be biblical in the sense of actually occurring in Scripture to be permissible. The Church, or part of it, simply recognizes something that has been done, even if invented out of whole cloth–like the saints can hear our prayers or that relics have power–and thus it becomes part of Holy Tradition. And their is no higher authority than Holy Tradition. It is the final word, above or on par with Scripture. This is EO’s version of holy Mormon underpants.