1"Luminous, bhikkhus, is this mind, but it is defiled by adventitious defilements." [n.46] At AN3.102 the word pabhassara is used to describe the mind (citta) that has attained concentration (samādhi). It thus seems that it is in deep samādhi that the intrinsic luminosity of the mind emerges, at least temporarily. AN5.23 says explicitly that the mind freed from the five hindrances is luminous (pabhassara) and properly concentrated for the destruction of the taints. See too MN111, where it is equanimity (upekkhā), presumably of the fourth jhāna, that is described as luminous.

1"Pabhassaramidaṁ, bhikkhave, cittaṁ. Tañca kho āgantukehi upakkilesehi upakkiliṭṭhan"ti.

Navamaṁ.