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