Just as God rested on the seventh day (the seventh day is the end of creation and encompasses within itself the time coextensive with the creation of this world) after He had created the world, so the world, having completed its course, will rest in God on the eighth and final day, the ogdoad, the eternal day. Everyone who exercises diligence with regard to virtue has in mind the future life. Its beginning is called the "eighth," for it follows this perceptible time when the number seven is dissolved. By necessity, we as human beings must establish a foothold in time and prudently use it if we wish to meet the eighth day of eternity. Thus the week of seven days falls back on itself, thereby forming a circle. Such a measure of time's totality exists until things endowed with motion cease and are supplanted by the eighth day. Eschatologically, the Lord's Resurrection is also seen as the eighth day, for it will bring about our own resurrection on the eighth day.
The economy of the ark at the deluge, in which eight persons among Noah's relatives were saved, indicates the salvific Ogdoad. Similarly, David was the eighth child among his brothers. The circumcision occurred on the eighth day, for it manifests the circumcision of the Ogdoad on high. The scriptures, when pointing to the number eight for our belief, have in mind the mystery of the Ogdoad.
2. Origen, Homilies on Exodus, PG 12.346C
The sixth day represents life here below: "God made the world in six days" [cf. Gen 1.31]. During this sixth day one must gather and put in reserve provisions sufficient for the (seventh) day to come. If you amass during this time treasures of justice, mercy, and pity, they will serve as nourishment in the age to come . . . But if one gathers good works, they will live for the next day. (This 'next day' is the Sabbath represented by the Ogdoad).
3. Eusebius of Caesarea, Commentary on the Psalms, PG 23.120A
The eighth day is the day of Christ the Lord's salvific resurrection on which we believe occurs the purgation of all sins. It is also symbolic of an infant's circumcision by which the soul is purged through regeneration by being begotten by God. This day is better than the seventh because on it the Law is dissolved.
4. Athanasius, Treatise on the Psalms, PG 27.75D
What is the eighth day? It is the day of the Lord's resurrection on which we receive the fruit of our labors. Indeed our enemies have been turned back with shame and confusion. This Psalm (Six) sings of that blessed time of repentance made for sin.
5. Didymus, Treatise on the Psalms, PG 39.1173D-76A
Psalm Six contains a more divine sense in its verses. It sings about the end, because (these verses) are the most perfect contemplation on the eighth day. The person is circumcised spiritually by God, for it is not carnal. Circumcision is perfected in the eighth day because it is extolled above the six days in which the world was made and attains the seventh day, the true, holy, and delightful Sabbath. Since perfect beatitude cannot be obtained through created things, we must assume a transcendent state, the eighth day.
6. Basil the Great, The Hexaemeron, PG 29.52 A
The day of the Lord is without evening, without succession, and without end. It is not unknown to scripture, and it is the day that the Psalmist calls the eighth because it is outside this time of weeks. Thus whether you call it day, or whether you call it eternity, you express the same idea.
7. Gregory the Theologian, On Pentecost, PG 36.432B
For the number seven, multiplied by itself, produces fifty minus one day, and we add this by taking it as the world to come: it is at once the first and the eighth, or rather one and indestructible. And indeed we must there cease the Sabbath-keeping of our souls, so that one part of seven may be given to some, of eight to others, as certain men who have come before us have explained.
8. John Chrysostom, On Compunction, PG 47.415D-16A
What is the eighth day? It is that great and glorious day of the Lord, a bright furnace at whose sight the virtues tremble and which manifests the hastening of the King. The eighth calls him, declaring him to a change of condition and a renewal of the future life. For the present life is none other than seven days which commences from the first day and is perfected in the seventh day.
