The Buddha says:
Bhikkhus, there are these Four Methods of Steadfast Mindfulness:
The bhikkhu keeps his mind steadfastly on the Body, with diligence, comprehension and mindfulness, thus keeping away covetousness and distress in the five khandhas.
When he keeps his mind steadfastly on the body, there is right and thorough understanding with regard to the body. When there is right and thorough understanding with regard to the body, there is realisation of Nibbana.
The bhikkhu keeps his mind steadfastly on Sensations (feelings) with diligence, comprehension and mindfulness, thus keeping away covetousness and distress in the five khandhas.
When he keeps his mind steadfastly on Sensation, there is right and thorough understanding with regard to Sensation. When there is right and thorough understanding with regard to Sensation, there is realisation of Nibbana.
The bhikkhu concentrates steadfastly on Mind (consciousness) with diligence, comprehension and mindfulness, thus keeping away covetousness and distress in the five khandhas.
When he concentrates steadfastly on Mind, there is right and thorough understanding with regard to Mind. When there is right and thorough understanding with regard to Mind, there is realisation of Nibbana.
The bhikkhu keeps his mind steadfastly on Mind-Objects (phenomena), with diligence, comprehension and mindfulness, thus keeping away covetousness and distress in the five khandhas.
When he keeps his mind steadfastly on Mind-Objects, there is right and thorough understanding with regard to Mind-Objects. When there is right and thorough understanding with regard to Mind-Objects, there is realisation of Nibbana.
