How can we understand this from a practical, a scientific point of view? All that is external is not in direct connection with you and is therefore unattainable in many cases. Therefore sometimes you can attain your wish, but many times you fail. By seeking the kingdom of God you seek the center of all that is within and without, and all that is in heaven and on earth is directly connected with the center. So, from the center, you are able to reach all that is on earth and in heaven but, when you reach what is not at the center, all may be snatched away from you.