Surah Al Mu'minun Tafseer

And those who believe in the Ayat of their Lord;

means, they believe in His universal and legislative signs, as Allah says about Maryam, peace be upon her:

وَصَدَّقَتْ بِكَلِمَـتِ رَبَّهَا وَكُتُبِهِ

and she testified to the truth of the Words of her Lord, and His Scriptures. (66:12),

meaning that she believed that whatever existed was by the will and decree of Allah, and that whatever Allah decreed, if it was a command, it would be something that He liked and accepted; if it was a prohibition, it would be something that He disliked and rejected; and if it was good, it would be true.

This is like the Ayah:

وَالَّذِينَ هُم بِرَبِّهِمْ لَاا يُشْرِكُونَ