CHĀNDOGYA UPANISHAD · 1.2.8

एवं यथाश्मानम् आखणम् ऋत्वा विध्वंसत एवं हैव स विध्वंसते य एवंविदि पापं कामयते यश् चैनम् अभिदासति ।
स एषो ऽश्माखणः ॥

evaṃ yathāśmānam ākhaṇam ṛtvā vidhvaṃsata evaṃ haiva sa vidhvaṃsate ya evaṃvidi pāpaṃ kāmayate yaś cainam abhidāsati ।
sa eṣo ’śmākhaṇaḥ ॥

Thus, as a ball of earth is scattered when hitting on a solid stone, will he be scattered who wishes evil to one who knows this, or who persecutes him; for he is a solid stone.