Tamāla Kṛṣṇa: "The Lord has explained in verse thirty-nine that by working under the principles of buddhi-yoga or Kṛṣṇa consciousness one can be relieved from the bondage of action and furthermore there is no flaw in the process. The same principle is more clearly explained in verse sixty-one, that this buddhi-yoga is to depend entirely on the Supreme or more specifically, on Kṛṣṇa, and in this way all the senses can be brought under control very easily. Therefore both the yogas are interdependent, as religion and philosophy. Religion without philosophy is sentiment or sometimes fanaticism, while philosophy without religion is mental speculation. The ultimate goal is Kṛṣṇa."
Prabhupāda: There are certain class of men who are simply philosophizing and there are certain class of men who are simply blindly following religious ritualistic process. So Bhagavad-gītā is combination of both. That is scientific. You should be religious, but should understand everything philosophically. Otherwise one becomes fanatic, religious fanatic. In the Caitanya-caritāmṛta it is clearly said that caitanyera dayāra kathā karaha vicāra. You people, you try to understand the gifts of Caitanya Mahāprabhu by your philosophical understanding. Not blindly, philosophically. And vicāra karile citte pāibe camatkāra. If you are actually a wise man, then you'll find it is sublime. And if you simply stick to your own religious ritualistic principles, don't try to understand the philosophy of everything, then you become a fanatic. So we should not become religious fanatics, nor dry mental speculators. Both these classes of men are dangerous. They cannot make any advance. The combination. You should be religious, but try to understand each and every line philosophically.