7 And lest I should be exalted above measure by the abundance of the revelations, a
thorn in the flesh was given to me, a messenger of Satan to buffet me, lest I
be exalted above measure.
8 Concerning this thing I pleaded with the Lord three times that it might depart
from me.
9 And He said to me, "My grace is sufficient for you, for My strength is made perfect
in weakness." Therefore most gladly I will rather boast in my infirmities, that
the power of Christ may rest upon me (2 Cor. 12:7-9).
God answers our prayers. Sometimes He grants our petitions, and sometimes He denies or delays our petitions because He knows best how to provide our needs and accomplish His will.
Paul had a "thorn in the flesh." We do not know the identity of this thorn, but it was looked upon as a hindrance and Paul wanted it to be removed. He prayed three times for its removal, but God saw things differently.
This infirmity actually provided an important service. Paul was given special revelations which qualified him to serve as an apostle. These privileges could cause a man to exalt himself before others. To prevent His servant from ruining himself with pride, God saw fit to "equip" Paul with an infirmity to keep him humble. Instead of removing the thorn, God granted Paul the strength to live with it, which caused him to place even greater trust in the power of Christ.
Just because we cannot see the positive response to our petitions does not mean God has not answered our prayers. "No" is an answer. May God grant us the faith and humility we need to accept the times that He says "No."