Because the five aggregates are impermanent, the well-studied disciple of the noble ones becomes disenchanted with form, sensation, perception, volitional formations, and consciousness.
Anicca sutta - Impermanence
Thus have I heard — At Sāvatthi.
There the Blessed One said this:
"Form, bhikkhus, is impermanent, sensation is impermanent, perception is impermanent, volitional formations are impermanent, consciousness is impermanent.
Seeing thus, bhikkhus, the well-studied disciple of the noble ones becomes disenchanted with form, becomes disenchanted with sensation, becomes disenchanted with perception, becomes disenchanted with volitional formations, becomes disenchanted with consciousness. Experiencing disenchantment, they become detached; through detachment, there is release. When released, there arises the knowledge: 'Released.'
'Birth is ended, the spiritual life has been lived, what had to be done has been done, there is no more coming to any state of being,' one understands."