The reason I post this question is due to a communist/atheist I know of who accused the Vedas of human sacrifice. As an attempt to refute his charge, I searched for and posted two of Srila Prabhupada's purports from Srimad Bhagavatam as follows:
"The tamasic sastras give instructions for the sacrifice of an animal like a goat or buffalo before the goddess Kali, but there is no mention of killing a man, however dull he may be. Even at this time there are many sacrifices being conducted without reference to the Vedic scriptures. For instance, in Calcutta recently a slaughterhouse was being advertised as a temple of the goddess Kali. Meat-eaters foolishly purchase meat from such shops, thinking it different from ordinary meat and taking it to be the prasada of goddess Kali. The sacrifice of a goat or a similar animal before the goddess Kali is mentioned in sastras just to keep people from eating slaughterhouse meat and becoming responsible for the killing of animals. The conditioned soul has a natural tendency toward sex and meat-eating; consequently the sastras grant them some concessions. Actually the sastras aim at putting an end to these abominable activities, but they impart some regulative principles so that gradually meat-eaters and sex hunters will be rectified." - Srimad Bhagavatam 5.9.15 (purport)
"According to the Vedic injunctions, only an aggressor can be killed...killing is not sanctioned in the sastras for other purposes. The killing of animals in sacrifice to the demigods, who are expansions of the Supreme Personality of Godhead, is sanctioned for those who eat meat. This is a kind of restriction for meat-eating. In other words, the slaughter of animals is also restricted by certain rules and regulations in the Vedas... Only thieves and rogues in the modes of passion and ignorance and maddened by material opulence offer a man in sacrifice before the goddess Kali. This is not sanctioned by the Vedic instructions." - Srimad Bhagavatam 5.9.17 (purport)
The statements above appeared to me to refute any claims of human sacrifice being endorsed in the Vedic literature. But then I searched further and found these quotes:
SB 9.7.20: Thereafter, in the sixth year, after wandering in the forest, Rohita returned to the capital of his father. He purchased from Ajigarta his second son, named Sunahsepha. Then he offered Sunahsepha to his father, Hariscandra, to be used as the sacrificial animal and offered Hariscandra his respectful obeisances.
SB 9.7.21: Thereafter, the famous King Hariscandra, one of the exalted persons in history, performed grand sacrifices by sacrificing a man and pleased all the demigods. In this way his dropsy created by Varuna was cured.
SB 9.7.22: In that great human sacrifice, Visvamitra was the chief priest to offer oblations, the perfectly self-realized Jamadagni had the responsibility for chanting the mantras from the Yajur Veda, Vasishtha was the chief brahminical priest, and the sage Ayasya was the reciter of the hymns of the Sama Veda.
SB 9.7.23: King Indra, being very pleased with Hariscandra, offered him a gift of a golden chariot.
Srimad Bhagavatam 9.16.31: Sunahsepha's father sold Sunahsepha to be sacrificed as a man-animal in the yajna of King Hariscandra. When Sunahsepha was brought into the sacrificial arena, he prayed to the demigods for release and was released by their mercy.
Purport: When Hariscandra was to sacrifice his son Rohita, Rohita arranged to save his own life by purchasing Sunahsepha from Sunahsepha's father to be sacrificed in the yajna. Sunahsepha was sold to Maharaja Hariscandra because he was the middle son, between the oldest and the youngest. It appears that the sacrifice of a man as an animal in yajna has been practiced for a very long time.
These quotes appear to countenance some human sacrifice, so now I am concerned about how to reply to that.