meat and drink

meat and drink (uncountable)

1. That on which somebody survives, or which makes their existence meaningful; means of subsistence.
   • 1811, An Exposition of the Old and New Testament

     The work he had done in instructing the woman; the work he had to do among the Samaritans; the prospect he now had of doing good to many, this was meat and drink to him; it was the greatest pleasure and satisfaction imaginable.