Forget not this one thing (en touto mh lanqanetw uma). Rather, "let not this one thing escape you." For lanqanetw (present active imperative of lanqanw) see verse 1 Peter 5 . The "one thing" (en) is explained by the oti (that) clause following. Peter applies the language of Psalms 90:4 about the eternity of God and shortness of human life to "the impatience of human expectations" (Bigg) about the second coming of Christ. "The day of judgment is at hand ( 1 Peter 4:7 ). It may come tomorrow; but what is tomorrow? What does God mean by a day? It may be a thousand years" (Bigg). Precisely the same argument applies to those who argue for a literal interpretation of the thousand years in Revelation 20:4-6 . It may be a day or a day may be a thousand years. God's clock (para kuriwi, beside the Lord) does not run by our timepieces. The scoffers scoff ignorantly.