Canto 1 - Boyhood
Bāla-kāṇḍa
Chapter 75: The History of the Bows of Lord Śiva and Lord Viṣṇu
Text 1.75.15

तदा तु देवताः सर्वाः पृच्छन्ति स्म पितामहम्।
शितिकण्ठस्य विष्णोश्च बलाबलनिरीक्षया॥

tadā tu devatāḥ sarvāḥ pṛcchanti sma pitāmaham
śitikaṇṭhasya
viṣṇoś ca balābala-nirīkṣayā

tadā tu = then; devatāḥ sarvāḥ = all the demigods; pṛcchanti sma = asked; pitāmaham = Grandfather Brahmā [who among the two is stronger]; śitikaṇṭhasya = among Lord Śiva; viṣṇoḥ = Lord Viṣṇu; ca = and; balābala-nirīkṣayā = desiring to see [who] is strong and [who is] weak.

Then, desiring to see [who] among Lord Śiva and Lord Viṣṇu is strong and [who is] weak, all the demigods asked Grandfather Brahmā [who among the two is stronger].

Tadā indicates that the demigods asked Brahmā this question after Lord Śiva destroyed Tripura, an extremely difficult task.