We are after designations. Someone wants to become "sir," someone wants to become "lord," someone wants to become the president or a rich man or a king or something else. As long as we are attached to these designations, we are attached to the body, because designations belong to the body. But we are not these bodies, and realizing this is the first stage in spiritual realization.
(Bhagavad-gita------introduction).

Anyone who is steady in his determination for the advanced stage of spiritual realization and can equally tolerate the onslaughts of distress and happiness is certainly a person eligible for liberation.
(Bhagavad-gita------2:15------purport).

The difficulties usually arise from having to sever family relationships, to give up the connection of wife and children. But if anyone is able to tolerate such difficulties, surely his path to spiritual realization is complete.
(Bhagavad-gita------2:15------purport).

A person in brahma-yoga, or Kṛṣṇa consciousness, is so absorbed in the loving service of the Lord that he loses his taste for material sense pleasure altogether. The highest pleasure in terms of matter is sex pleasure. The whole world is moving under its spell, and a materialist cannot work at all without this motivation. But a person engaged in Kṛṣṇa consciousness can work with greater vigor without sex pleasure, which he avoids. That is the test in spiritual realization. Spiritual realization and sex pleasure go ill together. A Kṛṣṇa conscious person is not attracted to any kind of sense pleasure, due to his being a liberated soul.
(Bhagavad-gita------5:21------purport).

The exact word used in Śrīmad-Bhāgavatam is paśu-ghna, which means killing animals or killing oneself. Persons who are not self-realized and who are not interested in spiritual realization are killing themselves; they are committing suicide. Because this human form of life is especially meant for self-realization, by neglecting this important part of his activities one simply wastes his time like the animals. So he is paśu-ghna.
(Krsna Book).

This association will help one develop factual devotional service to the Lord, which will cause all material misgivings to disappear like a flash of lightning. All these different stages of spiritual realization will be personally felt by the candidate, and this will create in him a firm belief that he is making positive progress on the way to the spiritual sky.
(Easy journey to other Planets).

One who is not self-controlled and whose mind is not undisturbed cannot practice meditation. Therefore, in the Bṛhan-nāradīya Purāṇa it is said that in Kali-yuga (the present yuga, or age), when people in general are short-lived, slow in spiritual realization and always disturbed by various anxieties, the best means of spiritual realization is chanting the holy name of the Lord.
(Bhagavad-gita------6:11-12------purport).

Only when a person performs pious activities and associates with saintly persons does spiritual knowledge dawn on his consciousness. Then, when he transcends the platform of duality—especially when he no longer takes part in the controversy over the Absolute Truth's monistic or dualistic existence—he sees Lord Kṛṣṇa in his enlightenment and worships Him with determination as one without a second, matchless and supreme. In the perfected stage of pious activities, the mode of goodness dominates the consciousness, dissipating the darkness of nescience and illusion, which are products of the mode of ignorance. As soon as the mode of passion is fully subdued, spiritual realization illuminates the sky of one's consciousness.
(Renunciation through Wisdom).

The living entity, while executing devotional service or transcendental rituals after many, many births, may actually become situated in transcendental pure knowledge that the Supreme Personality of Godhead is the ultimate goal of spiritual realization. In the beginning of spiritual realization, while one is trying to give up one's attachment to materialism, there is some leaning towards impersonalism, but when one is further advanced he can understand that there are activities in the spiritual life and that these activities constitute devotional service.
(Bhagavad-gita------7:19------purport).

In the perfected stage of pious activities, the mode of goodness dominates the consciousness, dissipating the darkness of nescience and illusion, which are products of the mode of ignorance. As soon as the mode of passion is fully subdued, spiritual realization illuminates the sky of one's consciousness.
(Renunciation through Wisdom).

Discussion of Kṛṣṇa is very potent, and if a fortunate person has such association and tries to assimilate the knowledge, then he will surely make advancement towardspiritual realization. Lord Kṛṣṇa, in order to encourage Arjuna to higher and higher elevation in His potent service, describes in this Ninth Chapter matters more confidential than any He has already disclosed.
(Bhagavad-gita------9:1------purport).

With the appearance of Śrī Kṛṣṇa within our heart, we become cleansed of the impurities of material contact, much as the morning appears new and fresh with the appearance of the sun. This is not a concoction of childish imagination but a factual experience of spiritual realization. One who has sincerely followed the footsteps of Śrī Kṛṣṇa or His bona fide servants has also realized this simple truth.
(Message of Godhead).

The Vedas are compared to the desire tree because they contain all things knowable by man. They deal with mundane necessities as well as spiritual realization. The Vedas contain regulated principles of knowledge covering social, political, religious, economic, military, medicinal, chemical, physical and metaphysical subject matter and all that may be necessary to keep the body and soul together. Above and beyond all this are specific directions for spiritual realization. Regulated knowledge involves a gradual raising of the living entity to the spiritual platform, and the highest spiritual realization is knowledge that the Personality of Godhead is the reservoir of all spiritual tastes, or rasas.
(Srimad Bhagavatam-------1:1:3------purport).

For spiritual realization one has to purify the heart and know things in their true perspective. As soon as one does this, the flow of one's natural affection begins to glide toward the Lord, and with the progress of this flow one becomes more and more self-realized in various relations with the Lord. The Lord is the center of all the affection of all living beings, who are all His parts and parcels.
(Light of the Bhagavata).

To become free from material conditions means to liberate the soul. As soon as one is, therefore, situated in absolute knowledge, his material conception of life is removed, or he emerges from a false conception of life. Thus the function of the pure soul is revived in spiritual realization.
(Srimad Bhagavatam-------1:15:31------purport).

There are different stages of spiritual development in matter. In the material world the spiritual sparks of the Personality of Godhead are covered by the material energy in different proportions, and gradually they become spiritualized in various species of life. The human form of life represents the complete development of the senses for spiritual realization of one's original affection for the Lord.
(Light of the Bhagavata).

Since the ultimate aim of life is spiritual realization, the direct way of invoking the holy name of the Lord, as mentioned above, is precisely recommended by Lord Caitanya, and people of the modern age can easily take advantage of this simple process, which is tenable for the condition of the complicated social structure.
(Srimad Bhagavatam-------2:6:26------purport).

Pious acts may lead a mundane creature toward the path of spiritual realization, but practical activity in the domain of devotional service to the Lord need not wait for the reactions of pious acts.
(Mukunda-Mala-Stotra).

The oneness of understanding that the Supreme Lord is fully spiritual and that in full spiritual realization one can understand what He is—the Supreme Personality of Godhead—is called kaivalya, or, in the language of Patañjali, realization of spiritual power. His proposal is that when one is freed from material desires and fixed in spiritual realization of the self and the Superself, that is called cit-śakti. In full spiritual realization there is a perception of spiritual happiness, and that happiness is described in Bhagavad-gītā as the supreme happiness, which is beyond the material senses.
(Srimad Bhagavatam-------3:21:12------purport).

When a living entity is fully surrendered, he is under the direct protection of Kṛṣṇa, and Kṛṣṇa gives him all intelligence by which he can advance in spiritual realization.
(Sri Caitanya Caritamrta------2:22:100-------purport).

Human society means that society which is making progress toward spiritual realization. The most advanced human society was known as ārya; ārya refers to those who are advancing. So the question is, "Which society is advancing?" Advancement does not mean creating material "necessities" unnecessarily and thus wasting human energy in aggravation over so-called material comforts. Real advancement is advancement toward spiritual realization, and the community which acted toward this end was known as the Āryan civilization.
(Srimad Bhagavatam-------3:21:52-54------purport).

The Personality of Godhead in His all-pervading feature of Paramātmā 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.
(Sri Caitanya Caritamrta------1:1:55-------purport).

By continuous, regular hearing, the effects of the contamination of lust and greed to enjoy or lord it over material nature diminish, and when lust and greed diminish, one then becomes situated in the mode of goodness. This is the stage of Brahman realization, or spiritual realization. In this way one becomes fixed on the transcendental platform. Remaining fixed on the transcendental platform is liberation from material entanglement.
(Srimad Bhagavatam-------3:27:21------purport).

With realization of these transcendental truths comes knowledge of the actual nature of the material energy in its pure form. And when these spiritual realizations gradually mature, one achieves a natural distance from the dualities of material nature. At this stage of spiritual development, the false ego is destroyed, all false identification and titles are removed, and we are liberated from the shackles of the illusory, material energy on the strength of our spiritual association with the Transcendence. No longer does māyā entangle us in material activities.
(Renunciation through Wisdom).