Yes, the sunnah, sometimes referred to as the hadi-th, the practice and example of the Prophet, is the second source of inspiration and instruction for Muslims. Belief in the sunnah is part of the Islamic faith.
A few examples of the Prophet's sayings (Hadith):
"God has no mercy on one who has no mercy for others."
"None of you truly believes until he wishes for his brother what he wishes for himself."
"He who eats his fill while his neighbor goes without food is not a believer."
"God does not judge you according to your bodies and appearances but He looks into your hearts and observes your deeds."
"One Muslim should do six acts of kindness to another: he should greet him when he meets him; accept his invitation when he gives one; say 'God have mercy on you' when he sneezes; visit him when he is ill; follow his bier when he dies; and like for him what he likes for himself."
"A man walking along a path felt very thirsty. Reaching a well he descended into it, drank his fill and came up. Then he saw a dog with its tongue hanging out, trying to lick up mud to quench its thirst. The man saw that the dog was feeling the same thirst as he had felt, so he went down into the well again and filled his shoe with water and gave the dog a drink. God forgave his sins for this action. The Prophet was asked: 'Messenger of God, are we rewarded for kindness towards animals?' He said, 'There is a reward for kindness to every living being.'"
"O People, listen to me in earnest, worship God, perform your five daily prayers (Salah), fast during the month of Ramadan, and give your wealth in Zakah. Perform Hajj if you can afford to. Know that every Muslim is the brother of another Muslim. You are all equal. Nobody has superiority over others except by piety and good action." (from The Prophet's Last Sermon).