Chapter XXXVII.—Of Rest in God Who Ever Worketh, and Yet is Ever at Rest.
52. For even then shalt Thou so rest in us, as now Thou dost work in us; and thus shall that be Thy rest through us, as these are Thy works through us. 1432 But Thou, O Lord, ever workest, and art ever at rest. Nor seest Thou in time, nor movest Thou in time, nor restest Thou in time; and yet Thou makest the scenes of time, and the times themselves, and the rest which results from time.
Compare his De Gen. ad Lit. iv. 9: “For as God is properly said to do what we do when He works in us, so is God properly said to rest when by His gift we rest.”