During meditation, we should not develop a mind which accumulates and holds on to things, but instead we develop a mind which is willing to let go of things, to let go of burdens. Outside of meditation we have to carry the burden of our many duties, like so many heavy suitcases, but within the period of meditation so much baggage is unnecessary. So, in meditation see how much baggage you can unload. Think of these things as burdens, heavy weights pressing upon you. I like to begin at the very simple stage of giving up the baggage of past and future.
Abandoning the past means not even thinking about your work, your family, your commitments, your responsibilities, your history, the good or bad times you had as a child…, you abandon all past experiences by showing no interest in them at all. As for the future, the anticipations, fears, plans, and expectations let all of that go too. This future is known to the wise as uncertain, unknown and so unpredictable. It is often complete stupidity to anticipate the future, and always a great waste of your time to think of the future in meditation.
When you have abandoned all past and all future, it is as if you have come alive. You are here, you are mindful. This is the first stage of the meditation, just this mindfulness sustained only in the present.
Ajahn Brahm, Sustained Attention on the Present Moment