Śikhā in Vedas

There are several references about Śikhā in vedas and smritis. These ancient texts have clear indication of the importance of śikhā in nitya and naimithika karma.

विना यच्छिखया कर्म विना विना यज्ञोपवीतकं|

राक्षसं तद्धि विज्ञेयं समस्या निष्फला क्रियाः||

In Vyasa Smriti, Vyasa says that Any karma performed without śikhā is considered as a karma performed by asuras.

स्नाने दाने जपे होमे संध्यायां देवतार्चने|

शिखा ग्रंथिं सदा कुर्यादित्येत तन्मनुरब्रवीत्||

Manu Smriti says that the śikhā must be tied when taking bath, performing dāna, japa, homa, and pitr karmas.

सदोपवीतिना भाश्यं सदा बद्ध शिखेन च|

विशिखो व्युपवीतश्च यत्करोति न तत्क्रुतम्||

Katyayani Smriti states that any satkarma such as yagna, dāna, or any dharmic karma performed without a śikhā do not give any fruitful results.