' Mind under control '...

Those who have given deep thoughts to the world are those who have controlled the activity of their minds.

Bowl of Saki, by Hazrat Inayat Khan
Commentary by Pir-o-Murshid Inayat Khan:

He is thoughtful whose mind is directed by his will, whose mind fulfills his intentions, whose mind is under the control of his intention. ... Only those who have controlled the activity of their minds have given deep thoughts to the world. Those whose minds are working mechanically like a machine, or just reflecting the activity of those around them, may appear to be living beings, but the mystic would say differently; for it is not till a person has gained mastery over his mind, till he is above this activity, that he is a ruling power, a true person.

When we think about it, we find that all the things that are accomplished in this world are accomplished by the power of mind. ... Whatever man creates in science, in art, in phenomena or wonder making, in poetry, in music, in pictures, in everything that he brings into being, is all achieved by the power of mind. ... If he does not control his mind, he is not a master but a slave. It lies with his own mind whether he shall be master, or whether he shall be slave. He is slave when he neglects to be master; he is master if he cares to be master.

Mastery lies not merely in stilling the mind, but in directing it towards whatever point we desire, in allowing it to be active as far as we wish, in using it to fulfill our purpose, in causing it to be still when we want to still it. He who has come to this has created his heaven within himself; he has no need to wait for a heaven in the hereafter, for he has produced it within his own mind now.

People pursue spirituality with their brain: that is where they are mistaken. Spirituality is attained through the heart. What do I mean by the heart? Is it the nervous center in the midst of the breast, the small piece of flesh that doctors call the heart? No, the definition of the heart is that it is the depth of the mind, the mind being the surface of the heart. That in us which feels is the heart, that which thinks is the mind. It is the same thing which thinks and feels, but the direction is different: feeling comes from the depth, thought from the surface. When thought is not linked with feeling it is just like a plant rising up from the earth, the root of which has not gone deep. A thought without feeling is a powerless thought; it is just like a plant without a deep root. A tree the root of which has gone deep into the earth is stronger, more reliable, and so the thought deeply rooted in the heart has greater power.