And alas for those who are with child and those who are nursing in those days! Pray that it may not happen in winter. (Mk.13:17-18)Reading these passages in isolation, one may come to the mistaken conclusion that God changes His mind. He means to do one thing, but then the prayers of His people cause Him to change course. But these verses from Mark do not exist in a vacuum. They are understood in the light of the larger corpus of Scripture, the Tradition that has come down from the Apostles, and the sense of the faithful throughout time; and all of these tell us of a God Who stands outside of and above space and time. He is perfect, not subject to change.
If the Lord had not shortened those days, no human being would be saved; but for the sake of the elect, whom he chose, he shortened the days. (Mk.13:20)
So what good do our prayers do? Why did Jesus tell the Apostles to pray and say that God would intervene in the tribulation for the sake of His elect? Let me hazard a partial answer: It's not that are prayers change God. Rather, He has already willed them. From eternity He has already woven them into His plan for the world, freely decided that some graces are released only in response to them. And this is preeminently true for regarding the prayer and intercession of Jesus! His human prayers for us, and His offering upon the Cross, and the torrent of grace they released have been woven into all of God's dealings with humanity. After all, even though Jesus' sacrificial death took place c.30 A.D., Scripture refers to Him as " the Lamb that was slain from the creation of the world" (Rev.13:8).
Keep those prayers coming my friends. God has woven your petitions into His plan for the unfolding of history - both your personal history and that of our world!