Intention (niyyah) in Islam refers to the spirit of doing deeds through which they may become religiously valid. Sincere intention turns permissible deeds into acts of worship.
Background
Like Tao in traditional Chinese medicine, which is the way to rich Qi energy, intent somehow is the way for all Muslims to reach unique God and Prophet Muhammad. In Islam, whatever that is done must be purely for God to be accepted by him and gives rewards for it. Even immigration from holy Mecca city to the newborn city Medina, (because of disturbance of non-believers) had rewards for only those people who did it for God's sake and his prophet when Muhammad was alive. Intention for human habits always exist, such as eating when human is hungry, the intention is to eat or when he is thirsty he intends to drink to fulfill his needs.
Here we understand that whatever a Muslim does has to be for God's sake to make him happy in the world and hereafter. Our deeds have to be right and have to be for God's happiness.