St. John Chrysostom says:
The Prophet David is not implying that our existence lasts only as far as this present life: perish the thought! After all, he is aware of the doctrine of the resurrection. Rather, it is that after our departure from here there would be no time for repentance. For the rich man praised God and repented, but in view of its lateness it did him no good [Luke 16:19-31]. The virgins wanted to get some oil, but no one gave any to them [Matthew 25:1-13]. So this is what this man requests, too, for his sins to be washed away in this life so as to enjoy confidence at the tribunal of the fearsome judge (St. John Chrysostom: Commentary on the Psalms, vol. I, trans. Robert C. Hill (Brookline, MA: Holy Cross Orthodox Press, 1998), p. 102).
St. Jerome says:
While you are still in this world, I beg of you to repent. Confess and give thanks to the Lord, for in this world only is he merciful. Here, He is able to be compassionate to the repentant, but because there He is judge, He is not merciful. Here, He is compassionate kindness; there, He is judge. Here, He reaches out His hand to the falling; there, He presides as judge (Homily on Psalm 105[106], quoted in Ancient Christian Commentary on Scripture: Old Testament, Vol. VII, Craig A. Blaising and Carmen S. Hardin, eds. (Downers Grove, IL: Intervarsity Press, 2008) p. 51).
St. Gregory the Theologian says:
It is better to be punished and cleansed now than to be transmitted to the torment to come, when it is the time of chastisement, not of cleansing. For as he who remembers God here is conqueror of death (as David has most excellently sung) so the departed have not in the grave confession and restoration; for God has confined life and action to this world, and to the future the scrutiny of what has been done (On His Father’s Silence, Oration 16:7).
St. Basil the Great says:
In like manner they which have grieved the Holy Spirit by the wickedness of their ways, or have not wrought for Him that gave to them, shall be deprived of what they have received, their grace being transferred to others; or, according to one of the evangelists, they shall even be wholly cut asunder—the cutting asunder meaning complete separation from the Spirit. The body is not divided, part being delivered to chastisement, and part let off; for when a whole has sinned it were like the old fables, and unworthy of a righteous judge, for only the half to suffer chastisement. Nor is the soul cut in two—that soul the whole of which possesses the sinful affection throughout, and works the wickedness in co-operation with the body. The cutting asunder, as I have observed, is the eternal separation of the soul from the Spirit. For now, although the Spirit does not suffer admixture with the unworthy, He nevertheless does seem in a manner to be present with them that have once been sealed, awaiting the salvation which follows on their conversion; but then He will be wholly cut off from the soul that has defiled His grace. For this reason “In Hades there is none that maketh confession; in death none that remembereth God,” because the help of the Spirit is no longer present (Treatise on the Holy Spirit, 40).