What is the meaning of "Ahlu al-Sunnah wa al- Jamaah"?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.

Ahlus-Sunnah Wal-Jamaa'ah are the people who hold fast to the Sunnah by their words and actions. They are the people who are very keen on following the example of the Salaf (the righteous predecessors) of the first three best generations, and the Prophet informed us about their superiority.   

Ahlus-Sunnah love the companions of the Prophet and his pure and pious wives, and their heart is free from any envy or hatred towards any Muslim.

In conclusion, whoever holds fast to the Sunnah and calls people to hold fast to what the companions where upon, like establishing the religion and supporting the Muslims, then he is one of them, and he will be resurrected on the Day of Judgement amongst them, Allaah willing.

Allaah knows best.