sāńkhya-yogau pṛthag bālāḥ
pravadanti na paṇḍitāḥ
ekam apy āsthitaḥ samyag
ubhayor vindate phalam

Translation of Bhagavad Gita 5.4

Only the ignorant speak of devotional service [karma-yoga] as being different from the analytical study of the material world [Sankhya]. Those who are actually learned say that he who applies himself well to one of these paths achieves the results of both.

Commentary by Sri A.C. Bhaktivedanta Swami Prabhupada of Gaudiya Sampradaya:

The aim of the analytical study of the material world is to find the soul of existence. The soul of the material world is Vishnu, or the Supersoul. Devotional service to the Lord entails service to the Supersoul. One process is to find the root of the tree, and the other is to water the root. The real student of Sankhya philosophy finds the root of the material world, Vishnu, and then, in perfect knowledge, engages himself in the service of the Lord. Therefore, in essence, there is no difference between the two because the aim of both is Vishnu. Those who do not know the ultimate end say that the purposes of Sankhya and karma-yoga are not the same, but one who is learned knows the unifying aim in these different processes.

Commentary by Sri Vishvanatha Chakravarthi Thakur of Gaudiya Sampradaya:

Your statement about which is the better of the two does not actually   apply,   because   intelligent  people do  not  see any difference between the two. The word sankya refers to being fixed in jnana. An anga of that is sannyasa. The fools, not the wise, speak of the difference between sannyasa and karma yoga. As the previous verse mentioned, “one should know the karma yogi to be the real sannyasi.” The sannyasi and karma yogi are one.

Commentary by Sri Ramanuja of Sri Sampradaya:

5.4 Those who say that Karma Yoga and Jnana Yoga are distinct because of the difference in results, are children, i.e., are persons with incomplete knowledge; they do not know the entire truth. The meaning is that they do not possess true knowledge, who say that Karma Yoga results in Jnana Yoga only and that Jnana Yoga alone results in the vision of the self and that the two are thus distinct because of the difference in their fruits. But on the contrary as both have only the vision of the self as the fruit, a person who is firmly set in one of them, wins that one fruit common to both. Sri Krsna further expounds the same:

Commentary by Sri Sridhara Swami of Rudra Sampradaya:

So it can be understood that both karma yoga or prescribed Vedic activities without desiring rewards includes renunciation of action as well when a person arrives at that realisation. Thus both paths can be practised in sequence according to a persons stage of spiritual development. The question of which one is factually superior is only applicable to the ignorant and misinformed as the discriminating and knowledgeable understand that the person who practices both thoroughly achieves the same result. The meaning Lord Krishna is intending is that they do not produce separate results.

Commentary by Sri Madhvacharya of Brahma Sampradaya:

Renunciation is certainly essential for the acquisition of spiritual wisdom which has been stated in Vedic scriptures as being impossible to acquire for one who is unable to relinquish enjoying the objects of the senses. If this is the case then how can it be assumed that renunciation is inferior to karma yoga or prescribed Vedic activities. Therefore Lord Krishna is explaining that both are inherent in each other and not contradictory. One who observes a yagna or offerings of worship to propitiate the Supreme Lord and experiencing the smoke arising from the ghee and seed grains offered to the fire reflects that the yagna is not sanctified due to its being performed for desires of the rewards upon its completion. But for the same yagna being performed without desires but solely for the propitiation of the Supreme Lord is considered the highest wisdom. Those that think otherwise are not conversant with the Vedic scriptures and thus their speculations do not need to be considered.

Commentary by Sri Keshava Kashmiri of Kumara Sampradaya:

How renunciation can apply to the yogi or the follower of the science of the individual consciousness attaining communion with the ultimate consciousness who is performing karma yoga or prescribed Vedic activities is being clarified here by Lord Krishna. The ignorant and uniformed mistakenly see these two paths as separate yielding divergent results; but this is not accepted by those who are self-realised as it has been seen that a person who determinedly follows either path achieves the same result.

Commentary by Sri Adi Shankaracharya of Advaita Sampradaya:

5.4 Balah, the fools; na panditah, not the learned ones; pravadanti, speak of; sankhya-yogau, Sankhya [Sankhya, i.e. monasticism, is that which is suited for sankhya, Self-inquiry.] (the Path of Knowledge) and (Karma-)yoga; as prthak, different, having opposite and different results. The learned ones, the wise, however, admit one, unconflicting result. How? Any one who samyak, properly; asthitah, resorts to, i.e. follows; ekam api, even one, between the Path of Knowledge and (Karma-) yoga; vindate, gets; phalam, the result; ubhayoh, of both. For, the result of both is that Liberation itself. Therefore there is no conflict with regard to the result. Objection: After beginning the topic with the words, ‘renunciation’ and ‘(Karma-) yoga’, how is it that the Lord speaks of the identity of the results of the path of Knowledge and (Karma-) yoga, which is beside the point? Reply: This defect does not arise. Although the question was put by Arjuna merely with regard to renunciation and Karma-yoga, yet the Lord, without actually avoiding them, and by adding something special which was intended by Him, gave the answer by expressing them through other words, ‘Sankhya’ and ‘(Karma-) yoga’. Those very ‘renunciation and ‘Karma-yoga’, when they are (respectively) associated with Knowledge and such of Its means as equanimity etc., are meant by the words ‘Sankhya’ and ‘yoga’. This is the Lord’s veiw. Therefore there is no discussion out of the context. How can the result of both be attained by the proper performance of only one? The answer is:

Commentary by Sri Abhinavagupta of Kaula Tantra Sampradaya:

5.4-5 Samkhya-Yogau etc. Yat samkhyaih etc. There is nothing to differentiate as ‘This is path of knowledge’ [and] ‘This is Yoga’. Indeed both these are ever inter-connected. Knowledge is not without Yoga; and Yoga also is not without knowledge. Hence the identity of these two.

Sanskrit Shloka Without Transliteration Marks:

sankhya-yogau prthag balah
pravadanti na panditah
ekam apy asthitah samyag
ubhayor vindate phalam

Sanskrit to English Word for Word Meanings:

sāńkhya — analytical study of the material world; yogau — work in devotional service; pṛthak — different; bālāḥ — the less intelligent; pravadanti — say; na — never; paṇḍitāḥ — the learned; ekam — in one; api — even; āsthitaḥ — being situated; samyak — complete; ubhayoḥ — of both; vindate — enjoys; phalam — the result.