Arjuna was not mature enough to withstand the viśvarũpa darshanam, because viśvarũpa darshanam is seeing the whole universe as the lord.  This means having a reverential attitude towards every event in creation.  If birth is an integral part of Bagawan, death is also an integral part of Bagawan.  So, accepting viśvarũpa darshanam means accepting the death of anyone at any time.  This means we should have a mature mind to accept any and all situations.  How do we make our minds mature?  We start with ishta devata or eka roopa appreciation.  Ishta devata bhakti can relieve our pain, and eventually develop viśvarũpa bhakti or aneka roopa bhakti.    

Verse 47

The lord said – Oh Arjuna! By my power this supreme has been shown to you by Me who am pleased with you.  Such a form of Mine which is radiant, universal, limitless and primal has not been seen by anyone other than you.

Krishna says I chose to show the viśvarũpa darshanam with the power of Maya Sakthi.  This viśvarũpa darshanam can be frightening for some and can be wonderful for others.

Yoga in this context refers to Maya Sakthi.

Verse 48

Neither by the study of vedas and yajnas nor by charity nor by rituals nor by severe austerities can I been seen in this form in the world of mortals by anyone other than you, Oh Arjuna!

Krishna highlights the bhakti as an important sadhana to appreciate viśvarũpa darshanam.  All sadhanas are equally important, but in some context to highlight a particular sadhana, scriptures will bring down other sadhanas.  In those instances, we should focus on the highlighted sadhana and not on the other sadhanas which may be criticized in those instances.  Bhakti or devotion alone will help in viśvarũpa darshanam.

Verse 49

Seeing such a frightening from of Mine, may you have neither fear nor delusion.  With a pleased mind free from fear, see again that very same form of Mine.

Appreciating the value of moksha itself requires tremendous maturity.  Scriptures do not force moksha but allow for us to work for artha and kama, but by following dharma.  Whatever the result, accept it as a blessing from the Lord.

Verse 50

Sanjaya said – Having said thus to Arjuna, Lord Krishna showed again His own form.  And, having assumed the pleasing form once again, the great Lord consoled that frightened Arjuna.

Arjuna requested to change the form and Krishna change the form from aneka roopa to eka roopa.  But Arjuna’s fear continues and Krishna consoles Arjuna by taking the original form.

Withdrawing viśvarũpa means withdrawing dhivya chakshu (a mind which is not over powered by ahankara and mamakara).  As long as one has ahankara and mamakara one will not be able to see totality or viśvarũpa.