When the mind seeks conviction or corroboration (through objective proofs and miracles as an aid to spiritual understanding), it is encroaching upon the sphere that properly belongs to the heart. Conviction and corroboration become important when a person desires guarantees for
securing certain definite and tangible results in the objective world. Even if we suppose that a person is intellectually convinced of the existence of God by means of miracles or some such objective data, this will not necessarily release his heart. The allegiance he might perhaps give to God as a result of such cold revelation will be either through fear or through a sense of duty. Love in which there is no sense of restraint cannot be born of a conviction that is based upon things accessible to the mind. And where there is no love, there is no bliss or beauty of being. In fact, God’s nature as the Ocean of Love cannot be grasped by the mind. God has to be known through love and not through an intellectual search for miracles.
That is the reason why I do not perform miracles for those who are closest and dearest to me. I would rather have no following than use miracles for convincing others of my divinity. It is true that, while loving me, people often do have spiritual experiences that were hitherto unknown to them; and these experiences help them in the further opening of their hearts. But they are not meant to feed the mental craving for intellectual conviction, and they should not be regarded as the goal.
-Discourses 7th Ed p96