SB 3.31.16

jñānaṁ yad etad adadhāt katamaḥ sa devas
 trai-kālikaṁ sthira-careṣv anuvartitāṁśaḥ
taṁ jīva-karma-padavīm anuvartamānās
 tāpa-trayopaśamanāya vayaṁ bhajema
Synonyms: 
jñānam — knowledge; yat — which; etat — this; adadhāt — gave; katamaḥ — who other than; saḥ — that; devaḥ — the Personality of Godhead; trai-kālikam — of the three phases of time; sthira-careṣu — in the inanimate and animate objects; anuvartita — dwelling; aṁśaḥ — His partial representation; tam — unto Him; jīva — of the jīva souls; karma-padavīm — the path of fruitive activities; anuvartamānāḥ — who are pursuing; tāpa-traya — from the threefold miseries; upaśamanāya — for getting free; vayam — we; bhajema — must surrender.
Translation: 
No one other than the Supreme Personality of Godhead, as the localized Paramātmā, the partial representation of the Lord, is directing all inanimate and animate objects. He is present in the three phases of time — past, present and future. Therefore, the conditioned soul is engaged in different activities by His direction, and in order to get free from the threefold miseries of this conditional life, we have to surrender unto Him only.
Purport: 

When a conditioned soul is seriously anxious to get out of the influence of the material clutches, the Supreme Personality of Godhead, who is situated within him as Paramātmā, gives him this knowledge: “Surrender unto Me.” As the Lord says in Bhagavad-gītā, “Give up all other engagements. Just surrender unto Me.” It is to be accepted that the source of knowledge is the Supreme Person. This is also confirmed in Bhagavad-gītā. Mattaḥ smṛtir jñānam apohanaṁ ca. The Lord says, “Through Me one gets real knowledge and memory, and one also forgets through Me.” To one who wants to be materially satisfied or who wants to lord it over material nature, the Lord gives the opportunity to forget His service and engage in the so-called happiness of material activities. Similarly, when one is frustrated in lording it over material nature and is very serious about getting out of this material entanglement, the Lord, from within, gives him the knowledge that he has to surrender unto Him; then there is liberation.

This knowledge cannot be imparted by anyone other than the Supreme Lord or His representative. In the Caitanya-caritāmṛta Lord Caitanya instructs Rūpa Gosvāmī that the living entities wander in life after life, undergoing the miserable conditions of material existence. But when one is very anxious to get free from the material entanglement, he gets enlightenment through a spiritual master and Kṛṣṇa. This means that Kṛṣṇa as the Supersoul is seated within the heart of the living entity, and when the living entity is serious, the Lord directs him to take shelter of His representative, a bona fide spiritual master. Directed from within and guided externally by the spiritual master, one attains the path of Kṛṣṇa consciousness, which is the way out of the material clutches.

Therefore there is no possibility of one’s being situated in his own position unless he is blessed by the Supreme Personality of Godhead. Unless he is enlightened with the supreme knowledge, one has to undergo the severe penalties of the hard struggle for existence in the material nature. The spiritual master is therefore the mercy manifestation of the Supreme Person. The conditioned soul has to take direct instruction from the spiritual master, and thus he gradually becomes enlightened to the path of Kṛṣṇa consciousness. The seed of Kṛṣṇa consciousness is sown within the heart of the conditioned soul, and when one hears instruction from the spiritual master, the seed fructifies, and one’s life is blessed.