This Sutta (AN 4.41: Samadhibhavana) shows four different ways of developing concentration or Stillness.
The four Jhana is shown as a way of developing a pleasant abiding only.
As I have learned all four developments shown in this Sutta are the results of letting go and abiding in Jhana.
Would be grateful for a feedback.
Samadhi has many useful features about it- 4 are mentioned here -pleasant abiding, clarity of mind, insight and arahanthood. This all depends on how that Samadhi is brought about. For example, focusing rather exclusively on the breath can lead to jhana. Focusing on the arising of five aggregates can lead to insight. (insight also requires samadhi).
Samadhi, in other words is required for both Samatha and Vipassana. We also know that Right mindfulness gives rise to the development of both those. Sati is the causative factor for samadhi. These factors are pretty intertwined…but not so much that they indistinct.
‘The individual who has attained internal tranquillity of awareness, but not insight into phenomena through heightened discernment, should approach an individual who has attained insight into phenomena through heightened discernment and ask him: ‘How should fabrications be regarded? How should they be investigated? How should they be seen with insight?’ The other will answer in line with what he has seen & experienced: ‘Fabrications should be regarded in this way. Fabrications should be investigated in this way. Fabrications should be seen in this way with insight.’ Then eventually he [the first] will become one who has attained both internal tranquillity of awareness & insight into phenomena through heightened discernment’. AN 4.94
Furthermore I think there is a mistake in this sutta. In the second and third paragraphs- perception of light should lead to clarity of mind:
'But if by doing this you don’t shake off your drowsiness, then attend to the perception of light, resolve on the perception of daytime, [dwelling] by night as by day, and by day as by night. By means of an awareness thus open & unhampered, develop a brightened mind. It’s possible that by doing this you will shake off your drowsiness. AN7.61
Watching the aggregates arise and pass away should lead to insight (and not clarity of mind).