16.1-5 It has been stated  [at the end of the last chapter] that  'by understanding this' etc.  The thing called  'understanding' comes to be  [in  the following] manner :  After the knowledge, born from hearing  [the scriptures etc.],  there arises a thought-process consisting of the logical analysis,  deliberation and  deep meditation that take the form 'This (what is taught in the scriptures etc.)  is like this'.  The above thought-process is of the nature  of investigation, critical examination and judgement.  From this thought-process one gains a good knowledge of a well practised from i.e., a contemplation of that object, free from the humiliation (influence) of different category.  When this is gained, understanding is achieved  Hence, it will be declared :
 'By critically examining in this way fully, act as you please'.  (Ch. XVIII, 63).
 
Here, only the preceptor and the scripture are mainly capable of creating the scriptural knowledge.  But in producing reasoning, deliberation and meditation the main cause is the capacity to examine critically a thing and  it is a special attribute of the pupil and it is an important one.  Therefore, with an idea that this is in Arjuna and with an intention to add a preparatory note to the purposeful statement  'By critically examining this, [act as you please]'; the Bhagavat, the preceptor, says  'Fearlessness etc.'
 
The Ignorance, born of the Tamas (Stand) occupies the devilish side.  This is repelled  (or removed) by the well augmented wisdom that takes hold of the divine part.  This is the nature of things [under estion]  'You  (Arjuna) have taken refuge in the divine part viz., wisdom, born of the Sattva (Strand).  Therefore shirking off the internal Ignorance in the nature of delusion, you should undertake the action, that has the sanction of the scriptures and that is of the nature of eradicating the external foe having the form of ignorance.'  Thus commences the [present] chapter.  Hence -
 Abhayam etc., upto pandava.  These are the identification marks of a person of divine parts.  [Hence] they are clearly identified.  Self-restraint :  subduing the sense organs.  Thought-lessness :  the perfarmance of action without examining the antecedent and the seel; its absence is the absence of thought-lessness.  Vital power :  the act of casting away [all] limitations by taking hold energy in the Self.  [All] this is the divine wealth and this is for your total emancipation, as it destroys craving.  Therefore, don't get sorrow like 'Having killed brothers etc., how can I (Arjuna) enjoy pleasure ?'  [The idea of] the rest  [of passage] is clear.