We have a law that says he ought to die is literally “We have a law, and according to that law he must die.” Here the pronoun we is emphatic. The law referred to is Leviticus 24.16, which demands the death penalty for blasphemy. In some languages it is not possible to say “a law says,” for a law cannot speak. However, the statement may be translated “We have a law, and according to that law he ought to die” or “… ought to be killed.”

For John, the real reason that the Jews wanted to put Jesus to death was because he claimed to be the Son of God (literally “he made himself God’s Son”). The Greek text does not have the definite article “the” before the phrase Son of God, and so New English Bible renders “he has claimed to be Son of God.” However, John’s statement that Jesus had said that God was his own Father and in this way had made himself equal with God (5.18) makes clear that Jesus’ claim was unique. Therefore it is better to render the Son of God, as most translations do. The crowd’s charge that Jesus claims to be the Son of God parallels the High Priest’s question in the Synoptic tradition: Are you … the Son of the Blessed God? (Mark 14.61). The clause because he claimed to be the Son of God must be expressed as direct discourse in some languages, for example, “because he said, ‘I am the Son of God.’ ”

Quoted with permission from Newman, Barclay M. and Nida, Eugene A. A Handbook on the Gospel of John. (UBS Handbook Series). New York: UBS, 1980. For this and other handbooks for translators see here .