Bhashya
अत्स्यन्नं दीप्ताग्निः सन् पश्यसि च पुत्रपौत्रादि प्रियमिष्टम् ।अन्योऽप्यत्त्यन्नं पश्यति च प्रियं भवत्यस्य सुतं प्रसुतमासुतमित्यादि कर्मित्वं ब्रह्मवर्चसं कुले, यः कश्चित् एतं यथोक्तम् एवं वैश्वानरमुपास्ते ।मूर्धा त्वात्मनो वैश्वानरस्य एष न समस्तो वैश्वानरः ।अतः समस्तबुद्ध्या वैश्वानरस्योपासनात् मूर्धा शिरस्ते विपरीतग्राहिणो व्यपतिष्यत् विपतितमभविष्यत् यत् यदि मां नागतोऽभविष्यः ।साध्वकार्षीः यन्मामागतोऽसीत्यभिप्रायः ॥
In plain words
With your digestive fire blazing, you eat food and look upon beloved children, grandchildren, and cherished things. Another person too eats food, beholds what is dear, and enjoys abundant progeny and spiritual radiance within his family—all through action—if he worships this very Vaiśvānara as described. But this head is merely a part of Vaiśvānara, not the entire Vaiśvānara. Because you worshipped a part as the whole with a mistaken grasp, your head would have shattered and fallen off had you not come to me. You acted wisely by coming to me—such is the meaning.
Close to the Sanskrit
Eating food, being of blazing fire, you see dear and desired sons and grandsons etc. Another also eats food, sees dear things, and there is son, well-born, intensely born etc., the fruit of action, and spiritual splendor in the family, whoever thus worships this Vaisvanara as stated. But the head of Vaisvanara is this self, not the whole Vaisvanara. Hence, due to worshipping Vaisvanara with the notion of wholeness, your head, of you who held a false conception, would have fallen off if you had not come to me. You did well that you came to me, this is the intent.