Bhagavad Gita · Vishvarupa Darshana YogaChapter 11, Shloka 50 (11.50)

Shankaracharya. svakaṃ vasudevasya gṛhe jātaṃ rūpaṃ — his own form, born in the house of Vasudeva; saumyavapuḥ prasannadehaḥ.

Acharya Ramanuja — the story of the four arms. aparicitasvarūpadarśanena bhītam enaṃ punar api paricitasaumyavapuḥ bhūtvā āśvāsayāmāsa — Arjuna, frightened by the unfamiliar form, was comforted by the familiar, gentle form; and the story: the son of Vasudeva's caturbhujam eva svakīyaṃ rūpam — at the prayer of Vasudeva, who feared Kamsa, ākaṃsavadhāt pūrvaṃ bhujadvayam upasaṃhṛtaṃ paścād āviṣkṛtaṃ ca — two arms were kept hidden until the slaying of Kamsa and revealed afterwards; with evidence from Vishnu Purana 5.3.10, 5.3.13; and even Shishupala (in his hatred) used to contemplate the four-armed form (Vi. Pu. 4.15.10).