A major share of the Reformation and puritan era held to post-millennialism, that only after the majority of the nations convert to Christianity (in the Millennium, Ps. 22:26-31; Isa. 2:2-5; Rev. 20:4; etc.) will Christ come again.
It is sometimes posed as an objection to this that Christ may come back at any time; therefore post-millennialism is not true. Yet most of Church history has recognized from Scripture that there are prophecies which must occur before Christ comes again; hence Christ cannot come at any time.
This article demonstrates from the Scriptures that the Lord’s standing at the door and coming quickly is consistent with a robust postmillennialism.
Fentiman, Travis – Postmillennialism and the Imminent Return of Christ 2018 22 pp.