When Jesus says that miracles are everyone's right, but purification is necessary first, it is because of the ways that you keep blocking miracles.
You DO have every right to access miracles and perform them, BUT, if you believe in sin, if you are riddled with guilt and fear, if you haven't done at least SOME purification of your mind, you're not going to be ABLE OR WILLING to perform miracles.
They're not being denied you, at all. There is no reason why you can't have miracles in your life ALL THE TIME. The only thing stopping it is you and your beliefs in the ego's world. That's why you need to purify, undo, forgive, and accept the atonement over and over again so that you can reconnect yourself with believing in GOD, and thereby rekindle the fire and regain ACCESS to the power of God.
And that access DOES NOT require you to be super perfect and enlightened. It works even with enough faith that it will work, believing in God enough "sight unseen", even if you don't fully believe. Open enough of a doorway and He will enter. Show Holy Spirit even a LITTLE WILLINGNESS and He will take your invitation!
There IS some 'conditions' for miracles to occur, and you can attain them, if you are willing to do some purification.