Some good scriptures to start with:
 
Jeremiah 29:11-14
'For I know the plans that I have for you,' declares the LORD, 'plans for welfare and not for calamity to give you a future and a hope. 'Then you will call upon Me and come and pray to Me, and I will listen to you. 'You will seek Me and find Me when you search for Me with all your heart. 'I will be found by you,' declares the LORD, 'and I will restore your fortunes and will gather you from all the nations and from all the places where I have driven you,' declares the LORD, 'and I will bring you back to the place from where I sent you into exile.'

Isaiah 53:4-5
Surely He has borne our griefs, sicknesses, weaknesses, and distresses and carried our sorrows and pains [of punishment], yet we ignorantly considered Him stricken, smitten, and afflicted by God. But He was wounded for our transgressions, He was bruised for our guilt and iniquities; the chastisement [needful to obtain] peace and well-being for us was upon Him, and with the stripes [that wounded] Him we are healed and made whole.

Mark 16:17-18
And these signs will accompany those who believe: In my name they will drive out demons; they will speak in new tongues; they will pick up snakes with their hands; and when they drink deadly poison, it will not hurt them at all; they will place their hands on sick people, and they will get well."

2 Corinthians 2:14
But thanks be to God, who always leads us in triumphal procession in Christ and through us spreads everywhere the fragrance of the knowledge of him.

Matthew 18:19
"Again, I tell you that if two of you on earth agree about anything you ask for, it will be done for you by my Father in heaven.

Matthew 21:21-22
Jesus replied, "I tell you the truth, if you have faith and do not doubt, not only can you do what was done to the fig tree, but also you can say to this mountain, 'Go, throw yourself into the sea,' and it will be done. If you believe, you will receive whatever you ask for in prayer."

Mark 11:24
Therefore I tell you, whatever you ask for in prayer, believe that you have received it, and it will be yours.

John 11:22
But I know that even now God will give you whatever you ask."

Luke 11:9-13
"So I say to you: Ask and it will be given to you; seek and you will find; knock and the door will be opened to you. For everyone who asks receives; he who seeks finds; and to him who knocks, the door will be opened. "Which of you fathers, if your son asks for[1] a fish, will give him a snake instead? Or if he asks for an egg, will give him a scorpion? If you then, though you are evil, know how to give good gifts to your children, how much more will your Father in heaven give the Holy Spirit to those who ask him!"

John 14:13-14
And I will do whatever you ask in my name, so that the Son may bring glory to the Father. You may ask me for anything in my name, and I will do it.

John 15:7
If you remain in me and my words remain in you, ask whatever you wish, and it will be given you.

John 15:16
You did not choose me, but I chose you and appointed you to go and bear fruit--fruit that will last. Then the Father will give you whatever you ask in my name.

John 16:23
In that day you will no longer ask me anything. I tell you the truth, my Father will give you whatever you ask in my name.

1 John 5:14-15
This is the confidence we have in approaching God: that if we ask anything according to his will, he hears us. And if we know that he hears us--whatever we ask--we know that we have what we asked of him.