Mantra 5

पञ्च मा राजन्यबन्धुः प्रश्नानप्राक्षीत्तेषां नैकंचनाशकं विवक्तुमिति स होवाच यथा मा त्वं तदैतानवदो यथाहमेषां नैकंचन वेद यद्यहमिमानवेदिष्यं कथं ते नावक्ष्यमिति ॥ ५.३.५ ॥

In plain words

A man of the princely class asked me five questions, and I could not answer a single one of them." He said, "As thou hast told me these questions, so I too do not know a single one of them. If I had known them, how should I not have told them to thee?"