Thank you for asking me.
In order to grow spiritually, we need spiritual nourishment. It is in contrast with material nourishment which encourages accumulation of more and more, and the chasing after material possessions. The more we have, the more we desire. This results in selfishness and greed. On the other spectrum, we seek to escape from the unpleasant things. We get upset when we are confronted with those things that we do not like. This is the nature of the world. Most often we are forced to associate with those that we do not like, while we don't seem to get enough of that which we desire. We get annoyed and in the extreme case we become hateful when we are irritated with the unpleasant.
In the life of a "normal" person, his life revolves around 3 things: I want; I don't want; and I don't care. The whole mindset is not conducive for spiritual growth. The whole system is stifled with greed, hatred, and delusion. There is no room for spiritual growth. Knowing this, a diligent Buddhist will cultivate certain values so as to reduce the greed, hatred, and delusion. First he has to start by reducing greed, by being more charitable. Second, he has to cultivate good moral principles which will help him overcome hatred. He has to be a good person without harming others. Third, he practises meditation in order to calm and train his mind to improve on his mission to reduce greed and hatred.
The Buddha's teachings can be summed up in 3 sentences:
Avoid doing evil (avoid greed and hatred)
Do good (practise good moral principles)
Purify the mind (through meditation)