Bhakthi

In Bhagavat Purana, in the story of Ambarisha and Durvasa, is this famous statement:

sadhavo hridayam mahyam

sadhunam hridayam tv aham

mad-anyat te na jananti

naham tebhyo manag api

“The pure devotee is always within the core of My heart, and I am always in the heart of the pure devotee. My devotees do not know anything else but Me, and I do not know anyone else but them.” (Bhag. 9.4.68)

Narada Bhakti Sutra says

Saatwasmin parama premaroopA,

Amrutaswaroopa cha

Unconditional intense love devotion to the unborn/undying nature (self) in everyone, everything and everywhere

man-mana bhava mad-bhakto

mad-yaji mam namaskuru

mam evaisyasi satyam te

pratijane priyo 'si me

Anvaya:

man-mana bhava..absorb your mind and heart in Me, mad-bhakto..become My devotee, mad-yaji..offer propitiation to Me, mam namaskuru..give humble obeisance unto Me, eva..surely, esyasi..you will come, mam..to Me, satyam pratijane..I promise this in truth, te..to you, asi..being, priyan..very dear, me..to Me.

Translation:

Absorb your mind and heart in Me, become My devotee, offer propitiation to Me, just give humble obeisance unto Me, and surely you will come to Me. I promise this in truth to you, being very dear to Me.

Bhagavad-Gita, chapter 18, verse 65

 jnanam visuddham paramartham ekam
anantaram tv abahir brahma satyam
pratyak prasantam bhagavac-chabda-samjnam
yad vasudevam kavayo vadanti

Srimad Bhagavatam 5.12.11

TRANSLATION: What, then, is the ultimate truth? The answer is that nondual knowledge is the ultimate truth. It is devoid of the contamination of material qualities. It gives us liberation. It is the one without a second, all-pervading and beyond imagination. The first realization of that knowledge is Brahman. Then Paramatma, the Supersoul, is realized by the yogis who try to see Him without grievance. This is the second stage of realization. Finally, full realization of the same supreme knowledge is realized in the Supreme Person. All learned scholars describe the Supreme Person as Vasudeva, the cause of Brahman, Paramatma and others.

vadanti tat tattva-vidas
tattvam yaj jnanam advayam
brahmeti paramatmeti
bhagavan iti sabdyate
(Bhag. 1.2.11)

From the very beginning, Srimad-Bhagavatam says, satyam param dhimahi: we meditate on the supreme truth. The supreme truth is explained here as jnanam visuddham satyam. The Absolute Truth is devoid of material contamination and is transcendental to the material qualities. It gives all spiritual success and liberation from this material world. That Supreme Absolute Truth is Krishna, Vasudeva. There is no difference between Krishna's inner self and outward body. Krishna is purna, the complete whole. There is no distinction between His body and soul as there is between ours.

tad viddhi pranipatena
pariprasnena sevaya
upadekshyanti te jnanam
jnaninas tattva-darsinah
(Bg. 4.34)

TRANSLATION: Try to learn the truth by approaching a spiritual master. Inquire from him respectfully, submissively and whole heartedly and render service unto him. The self-realized souls can impart knowledge unto you because they have seen the truth.

Bhaktha in Bagavad Geeta
Source: http://eawc.evansville.edu/anthology/gita.htm

1. Today I have described the same ancient science to you, because you are my sincere devotee and friend. Karma-yoga is a supreme secret indeed. (4.03)
2. Such (material) gains of these less intelligent human beings are temporary. The worshipers of Devas go to Devas, but My devotees come to Me. (7.23)
3. To those ever steadfast devotees, who always remember or worship Me with single-minded contemplation, I personally take responsibility for their welfare. (9.22)
4. Arjuna, even those devotees who worship demigods with faith, they too worship Me, but in an improper way. (9.23)
5. Worshippers of the demigods go to the demigods, the worshippers of the ancestors go to the ancestors, and the worshippers of the ghosts go to the ghosts, but My devotees come to Me (and are not born again). (See also 8.16) (9.25)
6. Such a person soon becomes righteous and attains everlasting peace. Be aware, O Arjuna, that My devotee never falls down. (9.31)
7. The one who does all works for Me, and to whom I am the supreme goal, who is my devotee, who has no attachment, and is free from enmity towards any being attains Me, O Arjuna. (See also 8.22) (11.55)
8. Arjuna said: Those ever-steadfast devotees (or Bhaktas) who thus worship You (as the manifest or personal God), and those who worship the eternal unmanifest (the formless or impersonal) Brahman (by developing Jnana), which of these has the best knowledge of yoga? (12.01)
9. The Supreme Lord said: Those ever steadfast devotees who worship with supreme faith by fixing their mind on Me as personal God, I consider them to be the best yogis. (See also 6.47) (12.02)
10. The yogi who is ever content, who has subdued the mind, whose resolve is firm, whose mind and intellect are engaged in dwelling upon Me; such a devotee is dear to Me. (12.14)
11. But those devotees who have faith and sincerely try to develop the above mentioned immortal virtues, and set Me as their supreme goal; are very dear to Me. (12.20)
12. Thus the creation as well as the knowledge and the object of knowledge have been briefly described. Understanding this, My devotee attains Me. (13.18)
13. The one who shall propagate this supreme secret philosophy (or the transcendental knowledge of the Gita) amongst My devotees, shall be performing the highest devotional service to Me and shall certainly attain (or come to) Me. (18.68)