The works of Ādi Śaṅkarācārya

Chāndogyopaniṣadbhāṣyam

Bhashya

Bhashya

यथा सोम्य एकेन नखनिकृन्तनेनोपलक्षितेन कृष्णाय-सपिण्डेनेत्यर्थः ; सर्वं कार्ष्णायसं कृष्णायसविकारजातं वि-ज्ञातं स्यात् ।समानमन्यत् ।अनेकदृष्टान्तोपादानं दार्ष्टा-न्तिकानेकभेदानुगमार्थम् , दृढप्रतीत्यर्थं च ।एवं सोम्य सआदेशः, यः मयोक्तः भवति ।

In plain words

Just as, gentle one, through a single iron nail-clipper every form made of iron is fully known, so it is here. The rest follows the same pattern. Multiple examples are given simply to help you grasp the various manifestations of reality and to anchor your understanding with absolute certainty. This, gentle one, is the core instruction I have given you.

Close to the Sanskrit

Just as, O gentle one, by one nail-clipper characterized as a lump of iron, all iron and the collection of iron modifications would be known. The rest is similar. The employment of multiple examples is for the purpose of understanding the multiple distinctions of the illustrated subject, and for firm conviction. Thus, O gentle one, is that instruction which is spoken by me.