Cindy applying that meaning to that scripture is very out of context
.Mat 19:25 When his disciples heard [it], they were exceedingly amazed, saying, Who then can be saved?
Mat 19:26 But Jesus beheld [them], and said unto them, With men this is impossible; but with God all things are possible.
This was said to men about God working in their lives, what we can not do ourselves He can do . This is not a proof text for God turing foreknowledge on and off.
A "sister" verse would be other verses like this
Jer 32:27 Behold, I [am] the LORD, the God of all flesh: is there any thing too hard for me? or Luk 18:27 And he said, The things which are impossible with men are possible with God.
God can not violate His own nature or He ceases to be God. It implies that God is not all knowing (omnipotent )
: "I am God, and there is none like me; declaring the end from the beginning, and from ancient times things that are not yet done; saying, My counsel shall stand, and I will do all my pleasure," Is. 46:10.
"Thou understandest my thoughts afar off," Psalm 139:2.
He "knoweth the heart," Acts 15:8.
"There is no creature that is not manifest in His sight; but all things are naked and laid open before the eyes of Him with whom we have to do," Heb. 4:13.