They will not be able to use this excuse simply because an...

They will not be able to use this excuse simply because an apparent hujjat (proof) didn't come to them because Allah gave them a hidden hujjat (proof) and that is intellect. The purpose of intellect is to allow one to be able to recognize his Creator. Not only this but it is also the responsibility of intellect to recognize the attributes of his Creator. The first attribute which intellect guides one towards is knowledge. Without knowledge, even making a simple ordinary clay pot is impossible.

Then how is it possible this entire universe can be created without knowledge? The second attribute which intellect guides one towards is ability. If a person does not also possess ability, then their knowledge is of no benefit. For example, even though a person might have knowledge regarding how to make a clay pot, but if he is disabled, he will not possess the ability to do so. The third attribute which intellect guides one towards is authority.

For example, if a person is thirsty and knows where the water is and has a bucket which to remove the water from the well, but the owner of the well does not permit him to draw water from the well, so despite having knowledge and ability, he still will not be able to remove his thirst. Therefore there are three essential requirements in order for one to be able to create something; knowledge, ability, and authority. The combination of these three is called wilayat.

Now it has been proven the purpose of intellect is to lead humanity towards wilayat. Purpose of Creation If a person has 1000 pots of biryani, he will only eat about 1-2 plates from it. So what will he do with the rest of the biryani? Only an insane person will simply leave it so that it goes to waste. Definitely a person with intellect will distribute it amongst the people.

Now from this example we can understand that the one who is the owner of this whole universe and has no need of it, what will He do with it? Certainly He will bestow His treasure upon His creation. This is an act of compassion. For this reason it is wajib (compulsory) that Allah must be compassionate. However He is also adl (just). Adl (justice) demands that before one can be blessed, he must first be deserving. Therefore Allah established a standard. Allah blesses those who meet the standard.