Asked is literally “said” (Revised Standard Version), but it introduces a question and so is better rendered asked in English. What God wants you to do of this verse and what God wants you to do of the following verse are literally “the works of God” and “the work of God.” The people raise the question in the plural (“works”) and Jesus answers in the singular (“work”). (See verse 29.) Here the meaning of the question is “What are the things we must do in order to get God’s approval?” New English Bible translates the question “Then what must we do if we are to work as God would have us work?” and Jerusalem Bible as “What must we do if we are to do the works that God wants?”

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 .