The best of advice and the most necessary is that you do not forget your Lord, and that you remember Him always, and do not rebel against Him, and that you should worship Him whether sitting or standing. Do not be dazzled by His blessings and always be grateful to Him. Do not go out from under the protective cover of His mercy, immensity and majesty, lest you go astray and fall into the field of destruction, even if affliction and adversity touch you and the fires of trials burn you. Know that the afflictions He sends are filled with the eternal marks of His honour, and that the trials He inflicts bring about His pleasure and nearness, even though it may be after some time. What blessings there are for the person who has knowledge, and who is granted success therein!
It is related that when someone asked the Messenger of Allah for advice, he said, 'Never get angry, for anger contains opposition to your Lord. Beware of making excuses, for they contain hidden polytheism. Say your prayers like someone saying farewell, for it contains a link to Allah and nearness to Him. Be modest before Allah as you are modest before the righteous among your neighbours, for this contains increased certainty.'
Allah has gathered up the advice of all our ancestors, both distant and near, into one single characteristic and that is Precaution (taqwa)
In the words of Almighty Allah,
Certainly We enjoined those who were given the Book before you, and [We enjoin] you too that you should be careful of [your duty]. (4:131)
This is the sum of every sound act of worship: it is by precaution that people reach the high degrees and highest ranks. It is by precaution that people lead a good life with constant companionship.
Surely those who guard [against evil] shall be in gardens and rivers, in the seat of honour with a most powerful King. (54:54-5)