Muhammad’s sayings and teachings are highly influential as they cover most aspects of life: spirituality, morals, social matters, commerce, and more. His sayings emanate from a base of wisdom and divine revelation.
Muhammad’s sayings, actions, and attributes are known as sunnah and are embodied in collections of sayings, or hadith. The sunnah represents the second source of Islamic legislation after the Quran.
Your companion [Muhammad] has not strayed from the path of truth nor has he been deluded. Nor does he speak out of whim."
Here is a selection of his sayings in relation to various life matters.
"Avail five before five:
Your youth before senility (old age)
Fitness before sickness
Wealth before poverty (needy)
Free time before busy time Life before death." (Narrated by Al Hakem)
"The perfect believers are those who have the best manners."
(Narrated by Tirmithi)
"Two graces, many people underestimate; health and free (leisure) time."
(Narrated by Bukhari, Tirmithi)
"Envy is forbidden except in two cases (you wish to have . The first one is a man on whom God bestowed wealth and he spends it righteously. The second case is a man on whom God bestowed wisdom and he acts according to it and teaches it to others."
"Make things easy to people (concerning religious matters), and do not make it hard for them; give them good tidings and do not make them run away."
"Those who do honest trading and business based on clear terms, God blesses them and their business (trade). On the contrary, God does not bless those who lie and hide facts."
"You will not be a believer in God unless you like for your brethren what you like for yourself."
"Every Muslim should pay Sadaqa (spend something for charity), if he didn’t find what to spend then let him work in order to benefit himself and be able to pay charity, if he didn’t find a job, then let him help others (this is an act of charity), if he didn’t find anyone to help, let him do good deeds and refrain from (avoid) doing bad or evil deeds. This is a charity for him."
"When a man dies, he gains no rewards except from people can continuously profit from, or he had left knowledge or a science that benefits the humanity, or if he had left a good (faithful) son who keeps on praying and asking God's blessings and forgiveness for his parents." (This is applicable to both males and females)
(Narrated by Muslim, Tirmithi, Nassa’i)
"Fear Allah wherever you are, follow a bad deed with a good deed as it erases it, and deal with people with high ethics."
(Tirmithi - 1987 & Ahmad 5/153)
"Goodness (rightness) is good morality; and sin (misdeed) is what embarrasses you (i.e. you are not comfortable within yourself ) and you hate it to be known by others."
A strong person is not the one who throws his adversaries to the ground. A strong person is he who contains himself when he is angry."
(Narrated by Bukhari, Muslim & Ahmad)
"Whoever believes in Allah and the Day of Judgment should say good (words) or keep silent and whoever believes in Allah and the Day of Judgment must honor (be generous with) his neighbor and whoever believes in Allah and the Day of Judgment must honor (be generous with) his guest."
(Bukhari, 6018 & Muslim 74-47)