1. We harbor unconfessed sin
2. Our request is not good for us
3.The timing is not right
4. God wants to test our persistence
5. We ask selfishly
For example, God said no to Jesus' prayer when he asked if he would take away the cup of suffering he encountered in the Garden of Gethsemane. God said no, not because he didn't empathize with Jesus' concern, but because he had a greater plan he needed his son to accomplish.
He said no to two of his disciples, James and John when they asked if they could sit on each side of him when he ruled his heavenly kingdom. He said no, not because he didn't love his two disciples, but because he knew their request was being asked for the wrong reasons.
Have you prayed for something to happen in your life and the answer has been "no? Then consider if one of the above reasons could be why God has said no to your prayer request. For just like he loved his son but said no to his request, God loves you and will at times say no to your prayers for a specific reason. And when he does, remember not to fret, because he always knows best.
Sharing the Word,
Prayer: Father, it hurts when you say no to my prayers, but help me to keep believing that you know what is best for me. Amen.