Sankarachariyar talked about the first three stages, karma yoga and upasana which are to be practiced in the first three ashramas.  Once the person has successfully gone through the first three stages, then he is ready for Jñāna yoga which is generally pursued in sanyasa ashrama.  Whether a person physically renounces or not is not the question.  A mind with a renunciation is ready for final sadhana which is Jñāna yoga.

First Sankarachariyar wants to emphasize that Jñānam must be pursued under the guidance of a guru alone.  Knowledge without a guru will give information but not transformation.  To learn anything, we go to a teacher.  We do accept exceptions to any rule and if there is anyone who becomes a Jñāni without a guru, that is an exception and not the rule.  Even if one gets knowledge without a teacher, we can accomplish the same thing faster with a teacher.  Two meanings of this verse:

1. May you approach a brahma Jñāni.
2. May you approach a competent Jñāni.  We should approach a Jñāni who has been a disciple of a guru, who has not studied independently.  This guru knows the traditional methods of teaching and communication.    

If we are approaching a vidwan and gain knowledge, that person must be alive.  Other mahatmas can be kept for inspiration and worship; for learning we require a live teacher. 

Why should we worship a teacher, a human being?  First, it helps weaken our ego.  Secondly, the scriptures are not going to speak to us directly.  Upanishads themselves do not speak to us and we get the upaniṣad teachings from the guru.  For the students, the guru is sasthram.  We must develop as much faith in the guru as much faith he has with the sasthram.  Physical actions like puja, namaskara etc. create an inner attitude of divinity. 

Once the rapport has been created and the channels have been opened, we may ask for brahma knowledge.  In this context, Brahman should be understood as brahma jñānam. Jñāna yoga consists of a threefold process of sravanam, mananam and nidhithyasanam. 

Systematic Study consist of:

1. Analysis of jivatma; anvaya vrithireka method, to find out the essential nature.  Whatever feature is there all the time that is my essential nature and permanent nature.  Whatever feature is incidental feature is temporary.   Another example is hot water; heat is not the essential nature of water; but fire has heat as the essential nature.  So, heat is the incidental nature of water and essential nature of fire.  Based on this, chit or awareness is the only essential nature of jivatma.
2. Analysis of paramatma; macrocosm by the method of adhyaropa apavara; through this analysis we come to the essential nature of totality, which is sat or pure existence.  The permanent and changeless nature of creation.  Everything else is subject to change.
3. Then come to the mahā vakya tat tvam asi; pure existence and pure consciousness are one and same.

Systematic, consistent study for a length of time is sravanam. 

Verse 3

Here Sankarachariyar briefly mentions sravanam, mananam and nidhithyasanam.  The upaniṣad vakyam does not convey the teaching explicitly or directly.  Mimamsa sasthram is the key to fully unlocking the meaning of vedanta.  Without mimamsa, vedas will be abstract and contradictory. 

In Kaivalya Upanishad, in one verse the Upanishad says from Brahman the panca buddha is born. (Around 12^th or 13^th verse).  Since all these are born from Brahman, Brahman is nirgunam and therefore, they are not there.  These two statements are contradictory. 

In Taittariya Upanishad, mantra is Sathyam, jñānam and anandam.  In the beginning it said Brahman is all pervading but now it says it entered everything.  These two are contradictory.   In mimamsa method, when a sentence is not clear, you do not go deep into the statement.  You arrive at the proper meaning by considering all other statements made by the Upanishads.  Then we will find the beautiful meaning conveyed by the statement.  Six factors of mimamsa are used to tie together all the Upanishad statement and arrive at the true meaning.  This is sravanam and by this you arrive at the conclusion that essence of jivatma is chit, essence of paramatma is sat.  And paramatma and jivatma are one and the same.  Aham Brahma Asmi.

Note regarding mimamsa:

Swamiji referred to six factors or Shadanga. They are:

1. Shabda (Word): Shabda refers to the words of the Vedic text, which are considered to be the ultimate authority. Mimamsa emphasizes the importance of analyzing and understanding the precise meaning of each word in the text.
2. Artha (Meaning): Artha refers to the meaning of the words in the Vedic text. Mimamsa believes that the true meaning of the text can only be understood by analyzing the words and their meanings in great detail.
3. Prayojana (Purpose): Prayojana refers to the purpose or goal of the Vedic text. Mimamsa emphasizes the importance of understanding the context and purpose of each text in order to properly interpret it.
4. Dosha (Fault): Dosha refers to any faults or contradictions in the Vedic text. Mimamsa believes that these faults must be identified and resolved in order to properly understand the text.
5. Samkhya (Inference): Samkhya refers to the process of inference or logical deduction. Mimamsa uses inference to draw conclusions and establish the meaning of the text.
6. Upapatti (Example): Upapatti refers to the use of examples to clarify the meaning of the text. Mimamsa believes that examples can help to illustrate complex ideas and make them easier to understand.