Do Not Think Evil Unwholesome Thoughts. Instead, Think of the Four Noble Truths

“Bhikkhus, do not think evil unwholesome thoughts; that is, sensual thought, thought of ill will, thought of harming. For what reason? These thoughts, bhikkhus, are unbeneficial, irrelevant to the fundamentals of the holy life, and do not lead to revulsion, to dispassion, to cessation, to peace, to direct knowledge, to enlightenment, to Nibbāna.“When you think, bhikkhus, you should think: ‘This is suffering’; you should think: ‘This is the origin of suffering’; you should think: ‘This is the cessation of suffering’; you should think: ‘This is the way leading to the cessation of suffering.’ For what reason? These thoughts, bhikkhus, are beneficial, relevant to the fundamentals of the holy life, and lead to revulsion, to dispassion, to cessation, to peace, to direct knowledge, to enlightenment, to Nibbāna.“Therefore, bhikkhus, an exertion should be made to understand: ‘This is suffering.’ An exertion should be made to understand: ‘This is the origin of suffering.’ An exertion should be made to understand: ‘This is the cessation of suffering.’ An exertion should be made to understand: ‘This is the way leading to the cessation of suffering.’”The Buddha's words/Vitakkasutta SN 56.7