John 8:35

These Jews thought of themselves as occupying a privileged and secure position as sons within God’s household because they were Abraham’s descendants. Jesus now informed them that they were not sons but slaves. The implication was that they did not enjoy a secure position but could lose it. This is really what happened because the Jews refused to receive Jesus (cf. Romans 9-11). They lost their privileged position in the world temporarily. Jesus was not speaking in this context about the loss of personal salvation but of the loss of Israel’s national privilege.

The son in Jesus’ explanation stands for Himself (John 8:36). The Greek word for "son" here is huios, which John consistently used to describe Jesus. He referred to believers as God’s "children" (Gr. tekna).