Skanda Purana — Avanti Khanda, Shloka 21
सन्ध्याहीनोऽशुचिर्नित्यमनर्हः सर्वकर्मसु । यदन्यत्कुरुते किंचिन्न तस्य फलभाग्भवेत्
sandhyāhīno'śucirnityamanarhaḥ sarvakarmasu | yadanyatkurute kiṃcinna tasya phalabhāgbhavet
ผู้ละเลยสันธยา ย่อมเป็นผู้ไม่บริสุทธิ์อยู่เสมอ และไม่สมควรแก่พิธีกรรมทั้งปวง; ต่อให้ทำสิ่งอื่นใด ก็ไม่เป็นผู้ได้รับผลแห่งกรรมนั้น
Skanda (deduced)
Scene: A cautionary scene: a person attempting offerings while a shadow of impurity clings; beside him, a disciplined practitioner performing sandhyā with clear light—showing ‘fruitless’ vs ‘fruitful’ action.
FAQs
Daily obligatory worship (nitya-karma) sustains purity and makes other religious acts spiritually effective.
No specific site is named; it is a universal dharma rule stated within Revā Khaṇḍa.
Do not omit Sandhyā-vandana; it is prerequisite for the fruit of other rites.