Tafseer : At-Tawbah 64

Mujahid said, “The hypocrites would say something to each other then declare, `We wish that Allah does not expose this secret of ours,” There is a similar Ayah to this one, that is, Allah’s statement,

And when they come to you, they greet you with a greeting wherewith Allah greets you not, and say within themselves: “Why should Allah punish us not for what we say” Hell will be sufficient for them; they will burn therein. And worst indeed is that destination! (Al-Mujadila 8)

Allah said in this Ayat

Say: “(Go ahead and) mock! But certainly Allah will bring to light all that you fear.”

He will expose and explain your reality to His Messenger through revelation. Allah said in other Ayat,

Or do those in whose hearts is a disease (of hypocrisy), think that Allah will not bring to light all their hidden ill-wills (Muhammad 29) until,

but surely, you will know them by the tone of their speech! (Muhammad 30)

This is why, according to Qatadah, this Surah is called `Al-Fadihah’ (the Exposing), because it exposed the hypocrites.