In what suttas are the "4 resolves" (adhiṭṭhānī) discussed?
MN 140.

Bhikkhu, this person has four foundations.’ So it was said. And with
reference to what was this said? There are the foundation of wisdom,
the foundation of truth, the foundation of relinquishment, and the
foundation of peace. So it was with reference to this that it was
said: ‘Bhikkhu, this person has four foundations.’
'One should not neglect wisdom, should preserve truth, should
cultivate relinquishment, and should train for peace.’ So it was said.
And with reference to what was this said?