1. Bhagavad-Gita As It Is Chapter 11.
Text 47-49
Devotee –
Not interested in seeing Universal Form.
Interested in loving reciprocation or worshipping Lord.
Only can see Universal Form.

2. Text 47 çré-bhagavän uväca mayä prasannena tavärjunedaà
rüpaà paraà darçitam ätma-yogät
tejo-mayaà viçvam anantam ädyaà
yan me tvad anyena na dåñöa-pürvam
The Supreme Personality of Godhead said: My dear Arjuna, happily have I shown you, by My internal potency, this supreme universal form within the material world. No one before you has ever seen this primal form, unlimited and full of glaring effulgence.

3. Exclusive
No one had seen this universal form of the Lord before Arjuna.
Other devotees in the heavenly planets and in other planets in outer space could also see it.
Duryodhana – was shown by Kåñëa some of His universal forms. But those forms are different from this one shown to Arjuna. It is clearly said that no one had ever seen this form before.

4. Text 48 na veda-yajïädhyayanair na dänair
na ca kriyäbhir na tapobhir ugraiù
evaà-rüpaù çakya ahaà nå-loke
drañöuà tvad anyena kuru-pravéra
O best of the Kuru warriors, no one before you has ever seen this universal form of Mine, for neither by studying the Vedas, nor by performing sacrifices, nor by charity, nor by pious activities, nor by severe penances can I be seen in this form in the material world.

5. Devotees – not interested in seeing Universal Form
Divine means godly. Unless one attains the status of divinity as a demigod, he cannot have divine vision.
It is not possible to decry Kåñëa and at the same time have the divine vision.
Those who are actually divine can see the universal form of the Lord.
The devotees, however, who are actually in the divine nature and who have divine vision, are not very much interested in seeing the universal form of the Lord.

6. Only devotees can see Universal Form
One can perform penances, give charity, study the Vedas, etc.—but unless he is a devotee like Arjuna, it is not possible to see that universal form.
It is clearly stated here that unless one becomes a devotee of Kåñëa one cannot see the universal form of God.

7. Text 49 mä te vyathä mä ca vimüòha-bhävo
dåñövä rüpaà ghoram édåì mamedam
vyapeta-bhéù préta-manäù punas tvaà
tad eva me rüpam idaà prapaçya
You have been perturbed and bewildered by seeing this horrible feature of Mine. Now let it be finished. My devotee, be free again from all disturbances. With a peaceful mind you can now see the form you desire.

8. Purpose of showing Universal Form
When the sons of Dhåtaräñöra tried to disrobe Draupadé in the assembly of the Kurus, Bhéñma and Droëa were silent, and for such negligence of duty they should be killed.
Kåñëa showed His universal form to Arjuna just to show him that these people were already killed for their unlawful action.
That scene was shown to Arjuna because devotees are always peaceful and they cannot perform such horrible actions.

9. Devotee – interested in loving reciprocation or worshipping Lord.
A devotee is not much interested in the universal form, for it does not enable one to reciprocate loving feelings.
Either a devotee wants to offer his respectful worshipful feelings, or he wants to see the two-handed Kåñëa form so that he can reciprocate in loving service with the Supreme Personality of Godhead.