The seven factors of enlightenment
1. Energy (~Effort)
4. Investigation (~knowledge)
After making a strong determination to go on practising and at the same time surrendering one may obtain a moment of consciousness with no object, except pure consciousness. This is called nibbana and has, when encountered the first time, a strong deconditioning effect. Wrong view leading to clinging to self, which is a major source of suffering (involving oneself, others and the world at large) has been eliminated. As a consequence there is no more (exisitential) doubt.
Three deeper levels of purification are possible in which greed, aversion, pride, sleepiness, restlessness, desire for existence and ignorance are rooted out. Then it has become quite easy to develop and maintain the qualities of ‘the heavenly places’: equanimity, loving-kindness, compassion, and shared joy.