If Allah should aid you, no one can overcome you; but if He should forsake you, who is there that can aid you after Him? And upon Allah let the believers rely. (3:160)
"If Allah willed He would have made you one nation, but that He may test you in what He has given you." (5:48)
The prophet (sawaw) said to ibn abbas: "if the whole nation were to gather together to benefit you they would only benefit you with that which Allah had already written you and if the whole nation were to gather to harm you they could only harm you with that which Allah had already written to harm you. The pen has been lifted and the ink has dried".