here is a quote from the Venerable Pa Auk Sayadaw's book 'The Working of Kamma' : PAGE 53
'For us properly to understand the workings of kamma, it is first of all
necessary to understand something about the workings of the mind. The
Buddha explains that when the mind is alert, then within a snap of the
fingers, very many thousand million consciousnesses arise and perish:
they arise as series, many thousand million mental processes (citta-
·vīthi). Most of them are mind-door processes: many thousand million
mind-door processes arising and perishing like a river in full flow.'
Aflame with the fire of passion, the fire of aversion, the fire of delusion.
Aflame, with birth, aging & death, with sorrows, lamentations, pains, distresses, & despairs ......
Seeing thus, the disciple of the Noble One grows disenchanted. SN 35.28