श्री शंकराचार्य - कुमतेः पुरुषाधमस्य

लुब्ध्वा सुदुर्लभतरं नरजन्म जंतुः
    तत्रापि पौरुषमतः सदसद्विवेकम् ।
संप्राप्य चैहिकसुखाभिरतो यदि स्यात्
    धिक् तस्य जन्म कुमतेः पुरुषाधमस्य ॥

- श्री शंकराचार्य

lubdhvA sudurlabhataram nara janma jantu
    tatrApi pauruShamataH sat asat vivekam ।
samprApya cha aihika sukhAbhirato yadi syAt
    dhik tasya janma kumateH puruSha adhamasya ॥

- shri shankarAchArya

After having got the rare (and most sought after) human birth, and been rewarded with courage and wisdom to judge right and wrong if you still indulge in all the material pleasures then such a bad person with bad mind will be damned.

- Sri Shankaracharya

श्री शंकरः - इन्द्रिय

तज्ज्ञानं प्रशमकरं यदिंद्रियाणां
    तज्ज्ञेयं यदुपनिषत्सु निश्चितार्थम् ।
ते धन्या भुवि परमार्थनिश्चितेहाः
    शेषास्तु भ्रमनिलये परिभमन्तः ॥

- श्री शंकरः

tat jnAnaM prashamakaraM yad indriyANAm
    tat jneyaM yad upaniShatsu niShcitArtham ।
te dhanyA bhuvI paramArtha nishcitehAH
    sheShAstu bhramanilaye paribhramantaH ॥

- shrI shankaraH

That is knowledge that can arrest the speed at which our senses drive our mind. The subject of our studies should be to know more about the cosmic spirit mentioned in the Upanishats. There are some lucky people in this world who know all about the spirit. The rest of them are wandering in the illusion of knowing it.

- Sri Shankara