The Buddha explains the importance of developing a radiant mind, a mind of loving-kindness and the consequences of negligence, diligence, and laziness.

Accharāsaṅghāta vagga - The Chapter On A Finger Snap

1.51

"Bhikkhus, this mind is radiant, but it is defiled by incoming defilements. The uninstructed ordinary person does not understand this as it truly is. Therefore, I say that there is no mental development for the uninstructed ordinary person."

First.

1.52

"Bhikkhus, this mind is radiant, and it is freed from incoming defilements. The instructed disciple of the noble ones understands this as it truly is. Therefore, I say that there is mental development for the instructed disciple of the noble ones."

Second.

1.53

"Bhikkhus, if a bhikkhu develops a mind of loving-kindness even for just the time of a finger snap, he is called a bhikkhu who is not devoid of jhāna, who lives in accordance with the Teacher's instruction, who follows his guidance, and who does not eat the country's alms food in vain. How much more, then, for those who practice it frequently?"

Third.

1.54

"Bhikkhus, if a bhikkhu develops a mind of loving-kindness even for just the time of a finger snap, he is called a bhikkhu who is not devoid of jhāna, who lives in accordance with the Teacher's instruction, who follows his guidance, and who does not eat the country's alms food in vain. How much more, then, for those who practice it frequently?"

Fourth.

1.55

"Bhikkhus, if a bhikkhu brings to mind a thought of loving-kindness even for just the time of a finger snap, he is called a bhikkhu who is not devoid of jhāna, who lives according to the Teacher's instruction, who follows his guidance, and who does not eat the country's alms food in vain. How much more, then, for those who practice it frequently?"

Fifth.

1.56

"Bhikkhus, whatever qualities are unwholesome, associated with unwholesomeness, and aligned with the unwholesome, all of them are preceded by the mind. The mind arises first for those qualities, and then unwholesome qualities follow."

Sixth.

1.57

"Bhikkhus, whatever qualities are wholesome, associated with wholesomeness, and aligned with the wholesome, all of them are preceded by the mind. The mind arises first for those qualities, and then wholesome qualities follow."

Seventh.

1.58

"Bhikkhus, I do not see any other single quality through which unarisen unwholesome qualities arise, or arisen wholesome qualities deteriorate, as I see in negligence. For the negligent one, bhikkhus, unarisen unwholesome qualities indeed arise, and arisen wholesome qualities decline."

Eighth.

1.59

"Bhikkhus, I do not see any other single quality through which unarisen wholesome qualities arise, or arisen unwholesome qualities decline, as I see in diligence. For the diligent one, bhikkhus, unarisen wholesome qualities indeed arise, and arisen unwholesome qualities decline."

Ninth.

1.60

"Bhikkhus, I do not see any other single quality through which unarisen unwholesome qualities arise, or arisen wholesome qualities decline, as I see in laziness. For the lazy one, bhikkhus, unarisen unwholesome qualities indeed arise, and arisen wholesome qualities decline."

Tenth.