Meaning
Supreme God Krishna spoke
The one who remains preoccupied with sensual delights, neglecting to contribute to the turning of the wheel thus set in motion, lives a sinful life and lives in vain, O Arjuna, son of Prithā! (3:16)
Sanskrit
श्रीभगवान् उवाच
एवं प्रवर्तितं चक्रं नानुवर्तयतीह यः ।
अघायुरिन्द्रियारामो मोघं पार्थ स जीवति॥
Word-by-word
एवम् प्र-वर्तितम् चक्रम् न अनु-वर्तयति इह यः,
अघ-आयुः इन्द्रिय-आरामः मोघम् पार्थ सः जीवति।।
Commentary
Lives in vain" does not apply to those saints and devotees who are not given to hedonistic pleasures (Indriyārāmah).^1 As the Lord clarifies in verse 16 onwards, they are not obliged to perform Vedic fire-yajnas. But such saints and devotees ought to follow one of the spiritual paths for union with God prescribed in the Holy Gitā by God, like Action Yoga, Knowledge Yoga, Devotional Yoga, and Meditative Yoga.
Another important point to consider is that the Lord doesn't entirely reject the Vedas and Vedic rituals. Verses 14 and 15 mention "karmas," or duties in a general sense, indicating that many duties advocated by the Vedas and Vedic texts are valuable for preserving the equilibrium of life on Earth and assisting humans in leading righteous lives.
Footnotes