O King, O hero, this human body is meant for universal benefits. If you kill this body untimely, you will kill all the benefits of human life.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
देहोऽयं मानुषो राजन् पुरुषस्याखिलार्थदः । तस्मादस्य वधो वीर सर्वार्थवध उच्यते
deho'yaṃ mānuṣo rājan puruṣasyākhilārthadaḥ | tasmādasya vadho vīra sarvārthavadha ucyate
SB 9.9.28