In Sutra of the Four Noble Truths, Buddha says:
You should know sufferings.
You should abandon origins.
You should attain cessations.
You should practise the path.
These instructions are known as the ‘four noble truths’. They are called ‘noble truths’ because they are superior and non-deceptive instructions.
In general, everyone who has physical or mental pain, even animals, understands their own suffering. But when Buddha says, ‘You should know sufferings’, he means that we should know the sufferings of our future lives. Through knowing these, we shall develop a strong wish to liberate ourself from them. This practical advice is important for everybody because, if we have the wish to liberate ourself from the sufferings of future lives, we shall definitely use our present human life for the freedom and happiness of our countless future lives. There is no greater meaning than this.
If we do not have this wish, we shall waste our precious human life only for the freedom and happiness of this one short life. This would be foolish because our intention and actions would be no different from the intention and actions of animals who are only concerned with this life alone. The Great Yogi Milarepa once said to a hunter called Gonpo Dorje:
Your body is human but your mind is that of an animal.
You, a human being, who possess an animal’s mind, please listen to my song.
Normally we believe that solving the problems and sufferings of our present life is most important, and we dedicate our whole life for this purpose. In reality, the duration of the problems and sufferings of this life is very short; if we die tomorrow, they will end tomorrow. However, since the duration of the problems and sufferings of future lives is endless, the freedom and happiness of our future lives is vastly more important than the freedom and happiness of this one short life. With the first noble truth, Buddha encourages us to use our present human life to prepare for the freedom and happiness of our countless future lives. Those who do this are truly wise.
A detailed explanation to help us understand future lives can be found in Appendices I and II.