insight = fruit of concentration by awareness
awareness = fruit of mindfulness
mindfulness = fruit of mindful breathing
The followings are excerpts from Thay's book titled "The Sun My Heart".
To be aware is to be aware of something. When the mind settles on the mountain, it becomes the mountain. When it settles on the sea, it becomes the sea. When we say "know," both the known and the knower are included. When we meditate on our body, we are our body; we limit our observations to our body, even though we realize that our body is not separate from the rest of the universe. If we meditate on limitless space, we become limitless space (akasanantyayatana). If we meditate on the consciousness which includes both space and time, we reach the state of limitless consciousness (vijiiananantyayatana). If we meditate on the absence of identity of all things, we enter the state of nothingness (akiiicanyayatana). If we meditate on the non-distinction between knower and known, we come to the state of "neither perception nor nonperception" (naivasaiijiianasaiijiiayatana). The Four Formless States of Consciousness are not as difficult to reach as you might think, provided awareness is there to shine on every movement of the mind.
When we meditate, we need to become one with the object. We should not stand outside of the object. If we live in awareness, it is very easy to reach The Four Formless States of Consciousness. The key is to stop thinking, or to stop mind.
Thích Nhất Hạnh