The conception of the virāṭ universal form of the Lord, as appearing in the material world, is imaginary. It is to enable the less intelligent [and neophytes] to adjust to the idea of the Lord’s having form. But factually the Lord has no material form.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
एतद्रूपं भगवतो ह्यरूपस्य चिदात्मनः । मायागुणैर्विरचितं महदादिभिरात्मनि
etadrūpaṃ bhagavato hyarūpasya cidātmanaḥ | māyāguṇairviracitaṃ mahadādibhirātmani
SB 1.3.30