In keeping with his method, Aquinas sets forth several objections, which he proceeds to answer one-by-one, but not before stating the contrary and offering an answer. To the contrary, he writes that "[i]t is written (Mark 13:32): 'Of that day or hour no man knoweth, neither the angels in heaven, nor the Son, but the Father.' The Son, however, is said not to know in so far as He does not impart the knowledge to us.
"Further, it is written (1 Thess. 5:2): 'The day of the Lord shall so come as a thief in the night.' Therefore seemingly, as the coming of a thief in the night is altogether uncertain, the day of the last judgment is altogether uncertain."
He then answers "that, God is the cause of things by His knowledge [*Cf. FP, Question [14], Article [8]]. Now He communicates both these things to His creatures, since He both endows some with the power of action on others whereof they are the cause, and bestows on some the knowledge of things. But in both cases He reserves something to Himself, for He operates certain things wherein no creature co-operates with Him, and again He knows certain things which are unknown to any mere creature. Now this should apply to none more than to those things which are subject to the Divine power alone, and in which no creature co-operates with Him. Such is the end of the world when the day of judgment will come. For the world will come to an end by no created cause, even as it derived its existence immediately from God. Wherefore the knowledge of the end of the world is fittingly reserved to God. Indeed our Lord seems to assign this very reason when He said (Acts 1:7): 'It is not for you to know the times or moments which the Father hath put in His own power,' as though He were to say, 'which are reserved to His power alone.'"
Let's also turn to Objection 3 and Reply to Objection 3 to clarify matters:
Objection 3: Further, the Apostle says (1 Cor 10:11): "It is on us ['These things . . . are written for our correction, upon whom the ends of the world are come'] that the ends of the world are come," and (1 John 2:18): 'Little children, it is the last hour,' etc. Since then it is a long time since these things were said, it would seem that now at least we can know that the last judgment is nigh."
Reply to Objection 3: "The statement, 'It is the last hour' and similar expressions that are to be found in Scripture do not enable us to know the exact length of time. For they are not intended to indicate a short length of time, but to signify the last state of the world, which is the last age of all, and it is not stated definitely how long this will last. Thus neither is fixed duration appointed to old age, which is the last age of man, since sometimes it is seen to last as long as or even longer than all the previous ages, as Augustine remarks (Qq. 83, qu. lviii). Hence also the Apostle (2 Thess. 2:2) disclaims the false signification which some had given to his words, by believing that the day of the Lord was already at hand."
As to the whole pre-millenarian dispensationalist view that posits the Rapture, it is very thin biblical gruel, indeed. Let's turn to St. Jerome for a commentary on Matthew 24:40-42:
"'Two men in one field' shall be found performing the same labour, sowing corn together, but not reaping the same fruit of their labour. The two 'grinding together' we may understand either of the Synagogue and the Church, which seem to grind together in the Law, and to make of the same Scriptures meal of the commandments of God; or of other heresies, which out of both or one Testament, seem to grind meal of their own doctrines."These reflections are not given to be definitive or complete, but just to show how the church deals with the passages of Scripture that Harold Camping is so badly abusing. I also want to refute the kind of biblical literalism that claims to know things like the day, month, and year of the flood and to make arthmetical predictions based such falsities by showing how, even from the time of St. Jerome (4th-5th centuries), we approach and interpret the sacred texts.
Indeed, dear friends in Christ, we pray the prayer of the Church from the beginning, "Maranatha," which means something like, "Come, Lord" Jesus (Rev. 22:20). Each time we attend Mass we acknowledge that we joyfully await His glorious return, not knowing the hour or the day, but, like the wise virgins, keeping our lamps trimmed and burning (Matt. 25:1-13). I love the part of the baptismal liturgy for children when the candle, lit from the Paschal candle, is given with these words: "Parents and Godparents, this light is entrusted to you to be kept burning brightly. This child of yours has been enlightened by Christ. S/He s to walk always as a child of the light. May s/he keep the flame of faith alive in his/her heart. When the Lord comes, may he (she) go out to meet him with all the saints in the heavenly kingdom."
It's easy to be ironic and smug about all of this, but given the confusion in the world and in the Church, especially the many who have taken Camping's prediction seriously and who will suffer as a result, the issue deserves at least some sober treatment.