Bhagavad Gita Chapter 07, Text 19

Bg 7.19

bahunam janmanam ante
jnanavan mam prapadyate
vasudevah sarvam iti
sa mahatma su-durlabhah

Word for word: 
bahunam — many; janmanam — repeated births and deaths; ante — after; jnana-van — one who is in full knowledge; mam — unto Me; prapadyate — surrenders; vasudevah — the Personality of Godhead, Krishna; sarvam — everything; iti — thus; sah — that; maha-atma — great soul; su-durlabhah — very rare to see.

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
After many births and deaths, he who is actually in knowledge surrenders unto Me, knowing Me to be the cause of all causes and all that is. Such a great soul is very rare.

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
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. Realizing this, he becomes attached to the Supreme Personality of Godhead and surrenders to Him. At such a time one can understand that Lord Sri Krishna’s mercy is everything, that He is the cause of all causes, and that this material manifestation is not independent from Him. He realizes the material world to be a perverted reflection of spiritual variegatedness and realizes that in everything there is a relationship with the Supreme Lord Krishna. Thus he thinks of everything in relation to Vasudeva, or Sri Krishna. Such a universal vision of Vasudeva precipitates one’s full surrender to the Supreme Lord Sri Krishna as the highest goal. Such surrendered great souls are very rare.

This verse is very nicely explained in the Third Chapter (verses 14 and 15) of the Svetasvatara Upanisad:

sahasra-sirsa purusah
sahasraksah sahasra-pat
sa bhumim visvato vrtva- 
tyatisthad dasangulam

purusa evedam sarvam
yad bhutam yac ca bhavyam
yad annenatirohati

“Lord Visnu has thousands of heads, thousands of eyes and thousands of feet. Entirely encompassing the whole universe, He still extends beyond it by ten fingers’ breadth. He is in fact this entire universe. He is all that was and all that will be. He is the Lord of immortality and of all that is nourished by food.” In the Chandogya Upanisad (5.1.15) it is said, na vai vaco na caksumsi na srotrani na manamsity acaksate prana iti evacaksate prano hy evaitani sarvani bhavanti: “In the body of a living being neither the power to speak, nor the power to see, nor the power to hear, nor the power to think is the prime factor; it is life which is the center of all activities.” Similarly Lord Vasudeva, or the Personality of Godhead, Lord Sri Krishna, is the prime entity in everything. In this body there are powers of speaking, of seeing, of hearing, of mental activities, etc. But these are not important if not related to the Supreme Lord. And because Vasudeva is all-pervading and everything is Vasudeva, the devotee surrenders in full knowledge (cf. Bhagavad-gita 7.17 and 11.40).