"Truly I tell you, if you have faith as small as a mustard seed, you can say to this mountain, ‘Move from here to there,’ and it will move. Nothing will be impossible for you." Matthew 17:20
"The prayer of a righteous person is powerful and effective." James 5:16
When I was growing up (and admittedly, still in the concrete stage of thinking, developmentally), I read the verses about how if we ask anything in Jesus's name, God would do it. And I believed it. So I remember one time in my room just laying there on my waterbed and praying that God would make me float in the air, in Jesus's name.
As you can imagine, he never really answered that prayer. And I know now that I didn't really understand what it meant to pray in Jesus's name--or to pray according to the things that are in his character and that would accomplish his purposes and his will.
But as I pray now for my friends, it often seems like my prayers are just as ineffective as those prayers that I would float. I pray daily that the Holy Spirit would break through into my friends' lives--that he would pour out his spirit on them, that their hearts would soften, that they would come awake spiritually, that the wounds caused them by Christians would heal. And I have no idea if those things are happening--sometimes I just can't see a bit of difference.
I think though, that although we are invited to rest on the promise that our prayers are effective and that God can (and does) move mountains, there is no sense of time in those Scriptures. We aren't told that if we pray today, the mountain will be gone tomorrow. And in a world of instant gratification of lightening-speed internet and microwave ovens, I don't think we have to wait very often.
But I think it takes a long time--years even--to melt a heart of stone. I think it takes a long time for people to change and be transformed. And I think those changes are made up of microscopic changes over a long period of time.
This is one of those areas where we have to have faith. We should persevere because we know that God is hearing our prayers, and if we are praying that God's will would be done, that his name would be glorified, and that his kingdom would come, we know that he will answer those prayers. He is answering those prayers. One day at a time.