Was Jesus' death a human sacrifice based on Romans 3:25 and Romans 5:6-11? Did God allow one human sacrifice? I know God hates human sacrifice. Thanks.
"Human sacrifice" is not an expression found in the Bible. Examples of child sacrifice are condemned - though the story of Abraham and Isaac features God testing Abraham by being prepared to sacrifice his son (God stops Abraham so it can be said that he does not intend
Isaac to be killed, but Abraham is rewarded for his being willing to do it).
The Greek word sometimes translated sacrifice in Romans 3:25 is "hilasterion" - google it for links to some interesting discussions - but sacrifice seems to me an inappropriate translation.
The word "thusia" is the common word for sacrifice, and is used of Christ in Ephesians 5:2 (but cannot bear some of the commentary put on it), and in Hebrews 9:26 and 10:12. In these verses it is clearly self-sacrifice, in a context where God does not want sacrifices at all (Psalm 40). Most of the sacrificial imagery is because scripture says that the blood of Christ saves/redeems/justifies/sanctifies/cleanses us. Perhaps the key verse is Hebrews 9:13/14, which contrasts how imperfect animal sacrifices could purify the flesh and Christ's blood purifies the conscience, an argument that leads to the statement (9:22) that without the shedding of blood there is no forgiveness of sins, and concludes with with Christ putting away sin by "his sacrifice of himself" (or simply "his sacrifice").
The idea of Christ as both "Priest and Victim" derives from Hebrews but Christ is not like other sacrificial victims - indeed, the word victim immplies unwillingness, as Christ is one who freely offers himself.