The easy (and correct) answer is that simply, there is only One God and that the Prophet Muhammad (saw) is His Messenger. With this, a Muslim holds strong to the Five Pillars of Islam and believes in each Pillar of Faith. But the Message of Islam is much, much more. It is a way of life, a guide, a teacher and a judge. It is a universal idea without discrimination. It knows no race, nationality, gender, or social class. It is compatible with daily life and is timeless. This world is not the final destination, but only a stop along the way.
The Message of Islam is ALLAH Subhana Wa Ta'ala Instructions to mankind, so that we may be successful in this part of our journey. A Muslim is commanded to do certain things, behave in certain ways, and learn and grow within the community. A Muslim must work and sweat for his or her wages and give generously to those who have little. Equality in economics, justice, politics, and family is essential. Neighborly kindness and support are incumbent. Parents, children, brothers, sisters, husbands, and wives have obligations and rights which form a balance in society. Acquiring knowledge and discipline, and learning how to deal fairly with those around you are challenges directly from ALLAH (swt). A Muslim knows how to handle these tasks by following the Message of Islam.