Oecumenius : For if God did not have a third rest, He would not have said: "Today, if you hear His voice, do not harden your hearts," so that there may be a rest into which those should enter who do not harden their hearts. Since obedience would be completely useless if there were neither rest nor reward. You have seen how he confirms it? "Do not harden your hearts so that you may enter into the rest," he says. For by saying that those who hardened their hearts did not enter into the rest, he implies that those who do not harden their hearts will enter. For every command of God has also a future reckoning. — The Pseudo-Oecumenian Catena on Hebrews Theodore of Mopsuestia : "Today" is neither an indefinite period of time, nor can it be predicated of an interval outside of "days" as if "today" were joined with each day. This should be stated not only for the sake of apostolic perspicuity but also for the sake of those who wish to understand, in the matter of the origin of the Only Begotten, the "I have begotten you today" by flatly asserting that the "today" is an indefinite period of time. They cannot perceive that if this were the case one would not be able to speak of a "today" since there was then not yet a day. The apostle has made clear that he would not say that "today" is an indefinite period of time when he said, "Again speaking in David he marks off a day." Also in another passage, "Comfort them every day until it will be called 'the Day.' " First he showed that the "today" is not being spoken of outside of "days," by his saying "every day," and so appending "until it will be called 'the Day.' " Then in the matter of the "day" it does not appear as if he were talking about an indefinite period of time which might be applied both to the time that has already passed and the time that is about to come. For what does he say? Deeming "each day" to be "the Day" which is spoken to we should give heed to remaining in the faith. For as "the Day" indicates the present day, he advises them to make full use of the day for that which is useful for exhortation. — FRAGMENTS ON THE EPISTLE TO THE Hebrews 4.4-7