Charles Spurgeon Commentary John 6:28-29

"They said therefore unto him, What must we do, that we may work the works of God? Jesus answered and said unto them, This is the work of God, that ye believe on him whom he hath sent." — John 6:28-29 (ASV)

Then said they unto him, What shall we do, that we might work the works of God? Jesus answered and said unto them, This is the work of God,—

The chief work, the greatest work which you can do.