Rig Veda 8.64.1-2: May our hymns please you; O lord of resolute will power, please display your bounty. May you drive off the Panis. May you crush with your foot the niggard churls who offer no homage. You are powerful; there is none so powerful as you are.
Who are panis and why Vedas are asking them to kill? Is it justified.
This is a reference from Rigveda 10.108 (mandala 10 sukta 108). From those reference, it is found that Pani is a group of demons (Asuras) kidnap the cattle of Angirasas (sons of sage Angiras). They hide those cows in a cave. Then Sarama is described to have found the cows by the path of truth.
There is no such proof in Vedas about their sacrifice. This can be the misinterpretation of of the vedic texts.
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