KeU 2.1
यदि मन्यसे सुवेदेति दहरमेवापि नूनं त्वं वेत्थ ब्रह्मणो रूपम् । यदस्य त्वं यदस्य देवेष्वथ नु मीमाँस्येमेव ते मन्ये विदितम्
If thou thinkest "I know It well," then it is certain that thou knowest but little of the Brahman (Absolute Truth), or in what form He (resideth) in the Devas (minor aspects of Deity). Therefore I think that what thou thinkest to be known is still to be sought after.
Translated by Swami Paramananda
The Teacher says: 'If thou thinkest I know it well; then thou knowest surely but little, what is that form of Brahman known, it may be, to thee?'
Translated by F. Max Müller