Ajahn Buddhadāsa Bhikkhu

Samadhi is the mind's energy gathered together and focused, which leads to great stability as well as great strength.

If we practice mindfulness with breathing, there will be enough samadhi.

So that if mindfulness brings wisdom, and then there is specifically applied wisdom working, if there is not quite enough strength to do the job, more samadhi can kick in in order to do the job totally, completely.

If you take some cutting tool like an axe or knife, you notice that not only it must be sharp, but it must have weight.

If you take a razor blade which is very sharp and try to cut down a tree, it will take you a very long time because the razor blade has no weight.

To cut something you need sharpness.

but there has to be weight behind it.

Wisdom is the sharpness and Samadhi provides the weight that provides the work.

One should observe the interconnectedness of these four things.

If there is no sati, then any wisdom we have is a waste.

No matter how much we have studied or know, how much we have meditated, in real life, if there is no mindfulness, then all our understanding is useless.

Or if there is no samadhi, we can be very wise, but if there is no samadhi,

The mind isn't firm and clear.

Then wisdom won't have the strength to deal with any problems.

And wisdom itself cannot develop without mindfulness, without samadhi.

Just to have two or three isn't enough.

We must develop all four of them and develop them in a way where they function as a team.

When we strengthen mindfulness, wisdom, wisdom in action and samadhi,

When these four are sufficiently strong and working as a unit, then these become our life mates, our partners in life, and enable us to be free of all dukkha.

And so through them, through developing them, this leads to more and more viveka.