It is our believe that Allah knows every thing and he created all this for us. But the question is that why Allah need to say this thing in Holy Quran ?. Why Allah need to tell us that He knows every thing ?. I think we only use that words and did not have full faith in it. We just use to move our tong but we never have a complete faith in it. Let us read the Holy Quran Verse first as mentioned below:
"He it is Who created for you all that is in the earth, and He directed Himself to the heaven, so He made them complete seven heavens, and He knows all things."
(Para No:1 & Verse No: 29)
If we have believe then why we are doing all the wrong deeds, why we doing the sins?. There are million question arises in the mind.