John 6:28 WEB

²⁶  Jesus answered them, 'Most assuredly I tell you, you seek me, not because you saw signs, but because you ate of the loaves, and were filled.

²⁷  Don't work for the food which perishes, but for the food which remains to eternal life, which the Son of Man will give to you. For God the Father has sealed him.'

²⁸  They said therefore to him, 'What must we do, that we may work the works of God?'

²⁹  Jesus answered them, 'This is the work of God, that you believe in him whom he has sent.'

³⁰  They said therefore to him, 'What then do you do for a sign, that we may see, and believe you? What work do you do?