Bg 12.1

arjuna uvāca
evaṁ satata-yuktā ye
bhaktās tvāṁ paryupāsate
ye cāpy akṣaram avyaktaṁ
teṣāṁ ke yoga-vittamāḥ
Synonyms: 
arjunaḥ uvāca — Arjuna said; evam — thus; satata — always; yuktāḥ — engaged; ye — those who; bhaktāḥ — devotees; tvām — You; paryupāsate — properly worship; ye — those who; ca — also; api — again; akṣaram — beyond the senses; avyaktam — the unmanifested; teṣām — of them; ke — who; yoga-vit-tamāḥ — the most perfect in knowledge of yoga.
Translation: 
Arjuna inquired: Which are considered to be more perfect, those who are always properly engaged in Your devotional service or those who worship the impersonal Brahman, the unmanifested?
Purport: 

Kṛṣṇa has now explained about the personal, the impersonal and the universal and has described all kinds of devotees and yogīs. Generally, the transcendentalists can be divided into two classes. One is the impersonalist, and the other is the personalist. The personalist devotee engages himself with all energy in the service of the Supreme Lord. The impersonalist also engages himself, not directly in the service of Kṛṣṇa but in meditation on the impersonal Brahman, the unmanifested.

We find in this chapter that of the different processes for realization of the Absolute Truth, bhakti-yoga, devotional service, is the highest. If one at all desires to have the association of the Supreme Personality of Godhead, then he must take to devotional service.

Those who worship the Supreme Lord directly by devotional service are called personalists. Those who engage themselves in meditation on the impersonal Brahman are called impersonalists. Arjuna is here questioning which position is better. There are different ways to realize the Absolute Truth, but Kṛṣṇa indicates in this chapter that bhakti-yoga, or devotional service to Him, is the highest of all. It is the most direct, and it is the easiest means for association with the Godhead.

In the Second Chapter of Bhagavad-gītā, the Supreme Lord explained that a living entity is not the material body; he is a spiritual spark. And the Absolute Truth is the spiritual whole. In the Seventh Chapter He spoke of the living entity as being part and parcel of the supreme whole and recommended that he transfer his attention fully to the whole. Then again in the Eighth Chapter it was said that anyone who thinks of Kṛṣṇa at the time of quitting his body is at once transferred to the spiritual sky, to the abode of Kṛṣṇa. And at the end of the Sixth Chapter the Lord clearly said that of all yogīs, one who always thinks of Kṛṣṇa within himself is considered the most perfect. So in practically every chapter the conclusion has been that one should be attached to the personal form of Kṛṣṇa, for that is the highest spiritual realization.

Nevertheless, there are those who are not attached to the personal form of Kṛṣṇa. They are so firmly detached that even in the preparation of commentaries to Bhagavad-gītā they want to distract other people from Kṛṣṇa and transfer all devotion to the impersonal brahma-jyotir. They prefer to meditate on the impersonal form of the Absolute Truth, which is beyond the reach of the senses and is not manifest.

And so, factually, there are two classes of transcendentalists. Now Arjuna is trying to settle the question of which process is easier and which of the classes is most perfect. In other words, he is clarifying his own position because he is attached to the personal form of Kṛṣṇa. He is not attached to the impersonal Brahman. He wants to know whether his position is secure. The impersonal manifestation, either in this material world or in the spiritual world of the Supreme Lord, is a problem for meditation. Actually, one cannot perfectly conceive of the impersonal feature of the Absolute Truth. Therefore Arjuna wants to say, “What is the use of such a waste of time?” Arjuna experienced in the Eleventh Chapter that to be attached to the personal form of Kṛṣṇa is best because he could thus understand all other forms at the same time and there was no disturbance to his love for Kṛṣṇa. This important question asked of Kṛṣṇa by Arjuna will clarify the distinction between the impersonal and personal conceptions of the Absolute Truth.