John 8:33

Jesus assumed that His hearers were slaves, but they emphatically denied being such. They could not have meant that they had never been physical slaves since the Egyptians, Assyrians, Babylonians, Greeks, Syrians, and most recently the Romans had all enslaved them. Probably they meant that they had never been spiritual slaves. They viewed themselves as spiritually right with God because of their descent from Abraham with whom God had made a special covenant (cf. Matthew 8:12; Mark 2:17; John 9:40). They denied that they had any significant spiritual need for liberation. Here were superficial believers in Jesus, believers in His messiahship only perhaps, who were resisting His teaching. They were not abiding in His word and being true disciples of His (John 8:31).