Allah's Dealing With People Including Atheist And Agnostics
The profession of God, the creator is innate, present in our nature. Those who did not receive any divine message will be judged for their response to this call of nature. See th verses: 7: 172-173 وَإِذْ أَخَذَ رَبُّكَ مِن بَنِي آدَمَ مِن ظُهُورِهِمْ ذُرِّيَّتَهُمْ وَأَشْهَدَهُمْ عَلَىٰ أَنفُسِهِمْ أَلَسْتُ بِرَبِّكُمْ ۖ قَالُوا بَلَىٰ ۛ شَهِدْنَا ۛ أَن تَقُولُوا يَوْمَ الْقِيَامَةِ إِنَّا كُنَّا عَنْ هَٰذَا غَافِلِينَ ‎﴿١٧٢﴾‏ أَوْ تَقُولُوا إِنَّمَا أَشْرَكَ آبَاؤُنَا مِن قَبْلُ وَكُنَّا ذُرِّيَّةً مِّن بَعْدِهِمْ ۖ أَفَتُهْلِكُنَا بِمَا فَعَلَ الْمُبْطِلُونَ ‎ Those who receive God’s message will be judged for their response to the message they received which also asks to believe in the hereafter. Those who would genuinely disbelieve may put their excuse to God and God with all his knowledge will judge them for their honesty and decide accordingly.
One has to build a case to reject the idea of God as innate in human nature. If he is honest, in his rejection (which practically seems not possible) God has the authority to excuse him. We will see in the hereafter.