Speak no more unto Me of this matter. Deuteronomy 3:26
We are to pray without ceasing; always praying, never fainting; asking, seeking, knocking. But there are some subjects concerning which God says, "Speak no more unto Me of this." In some cases these topics have to do with others, but more often with ourselves, as in the case of the Apostle Paul (2Co 12:9).
It is an awful thing when God says of certain individuals, Ephraim is joined to idols, let him alone; and when the conviction is wrought within us that the sin unto death is being committed, concerning which even the Apostle John said, "I do not say that he should pray for it." Such times come comparatively rarely; and so long as you feel able to pray for another, so long as no negative has been spoken, you may be sure that God waits to be entreated, and that your prayer will assuredly be answered.
But have you not realized at times that God has said about some earthly boon you were craving?-'' Child, do not ask Me more, leave it with Me. I know what you want, and what is best for you. Seek first My kingdom, and all these things, literally or in their equivalent, shall be added." It is well when we have been praying eagerly, to allow God's winnowing-fan to pass over our petitions, to winnow away all that is not in His mind to give; so that only those desires may remain which His Spirit has indicted, and which He is therefore pledged to bestow. If He does not give the exact thing you ask, He will give the Pisgah view and more grace. He will say to you, as to Paul, "My grace is sufficient for thee: for my strength is made perfect in weakness."