The Personality of Godhead in His all-pervading feature of Paramatma enters every entity, from the biggest to the most minute. His existence can be realized by one who has the single qualification of submissiveness and who thereby becomes a surrendered soul. The development of submissiveness is the cause of proportionate spiritual realization, by which one can ultimately meet the Supreme Lord in person, as a man meets another man face to face.
His Divine Grace A. C. Bhaktivedanta Swami Prabhupada
Sri Chaitanya-charitamrita, Adi-lila 1.55, Purport

The only duty of the most merciful persons is to transform the degraded taste of people. If you can save even one person from the great force of maha-maya, then that will be a greater act of philanthropy than opening millions of hospitals.
Srila Bhaktisiddhanta Sarasvati Thakura
64 Principles for Community, Principle 21

The Supreme Lord, who is greater than the greatest, becomes submissive to even a very insignificant devotee because of his devotional service. It is the beautiful and exalted nature of devotional service that the infinite Lord becomes submissive to the infinitesimal living entity because of it. In reciprocal devotional activities with the Lord, the devotee actually enjoys the transcendental mellow of devotional service.
Sri Chaitanya Mahaprabhu
Sri Chaitanya-charitamrita, Adi-lila 7.145

When a diseased eye is treated with medicinal ointment it gradually recovers its power to see. Similarly, as a conscious living entity cleanses himself of material contamination by hearing and chanting the pious narrations of My glories, he regains his ability to see Me, the Absolute Truth, in My subtle spiritual form.
Lord Sri Krishna
Srimad-Bhagavatam 11.14.26

The Supreme Personality of Godhead is a magician, and the material world is His magical show.
Svetashvatara Upanishad 4.10

Nothing is higher than the Supreme Person. The Supreme Person is the highest.
Katha Upanishad 1.3.11

The impersonalist conception of the identity of the individual and the Supreme is a preposterous phantasmagoria, like the horn of a rabbit. It has no reference to reality, and it is completely rejected by the people in general. They do not accept it. Those few texts of the Upanishads that apparently teach the impersonalist doctrine are interpreted in a personalist way by the author, Vyasadeva himself.
Srila Baladeva Vidyabhushana
Commentary on Vedanta-sutra 1.1.2

The Personality of Godhead is pure, being free from all contaminations of material tinges. He is the Absolute Truth and the embodiment of full and perfect knowledge. He is all-pervading, without beginning or end, and without rival.
Lord Brahma
Srimad-Bhagavatam 2.6.40