श्रीभगवान् बोले -- मेरा यह जो रूप तुमने देखा है, इसके दर्शन अत्यन्त ही दुर्लभ हैं। इस रूपको देखनेके लिये देवता भी नित्य लालायित रहते हैं।

purport by srila prabhupada -

In the forty-eighth verse of this chapter Lord Krishna concluded revealing His universal form and informed Arjuna that this form is not possible to be seen by so many pious activities, sacrifices, etc. Now here the word su-durdarsham is used, indicating that Krishna’s two-handed form is still more confidential.

by ramsukhdas -

 व्याख्या --   सुदुर्दर्शमिदं रूपं दृष्टवानसि यन्मम -- यहाँ सुदुर्दर्शम् पद चतुर्भुजरूपके लिये ही आया है ! विराट्रूप या द्विभुजरूपके लिये नहीं। कारण कि विराट्रूपकी तो देवता भी कल्पना क्यों करने लगे और मनुष्यरूप जब मनुष्योंके लिये सुलभ था. तब देवताओंके लिये वह दुर्लभ कैसे होता इसलिये सुदुर्दर्शम् पदसे भगवान् विष्णुका चतुर्भुजरूप ही लेना चाहिये जिसके लिये देवरूपम् (11। 45) और स्वकं रूपम् (11। 50) पद आये हैं।

i'm confused about this two commentaries because one says two-handed form and other commentary says four handed because in many instances demigods have seen four handed form like at the time of samudra manthan many demigods and asuras seen four handed form of bhagwan when lord lifting mandar mountain..also at the time of some wars like when personality of godhead killed kaalnemi..etc..also in dwapar on earth many human beings seen krishna's two handed form...so that 'sududarshanam' word is for vishwaroopa ?