This was said by the Lord…

“Bhikkhus, these three kinds of unwholesome thoughts produce blindness, lack of vision, and absence of knowledge; they obstruct wisdom, lead to vexation, and are not conducive to Nibbāna. What are the three? A sensual thought, a thought of ill will, and an aggressive thought. These, bhikkhus, are the three kinds of unwholesome thoughts that produce blindness … and are not conducive to Nibbāna.

“Bhikkhus, these three kinds of wholesome thoughts remove blindness and produce vision, knowledge, and the growth of wisdom; they do not lead to vexation and are conducive to Nibbāna. What are the three? A thought of renunciation, a thought of friendliness, and a thought of harmlessness. These, bhikkhus, are the three kinds of wholesome thoughts that remove blindness … and are conducive to Nibbāna.”

Three wholesome thoughts should be entertained,
Three unwholesome thoughts rejected.
One who stops such trains of thought
As a shower settles a cloud of dust,
With a mind that has quelled such thoughts
Attains in this life the state of peace.