The Existence of Allah سبحانه وتعالى in Quran and Hadeeth.

Ibn ‘Abbaas (may Allah be pleased with them) narrated on the authority of the Prophet (صلى الله عليه وسلم) that he said:
“Allah, Blessed and Exalted be He, took the covenant at Na‘maan (i.e., ‘Arafah), from the loins of Adam. He extracted from his loins every soul that Allah has predestined to be created, and He spread them before Himself like ants, then He spoke to them directly (what means): And mention when your Lord took from the children of Adam—from their loins—their descendants and made them testify of themselves, saying to them, "Am I not your Lord?" They said,
"Yes, we have testified." This lest you should say on the day of Resurrection, "Indeed, we were of this unaware. Or lest you say, "It was only that our fathers associated others in worship with Allah before, and we were but descendants after them. Then would You destroy us for what the falsifiers have done? Quran 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 (172)أَوْ تَقُولُوا إِنَّمَا أَشْرَكَ آبَاؤُنَا مِن قَبْلُ وَكُنَّا ذُرِّيَّةً مِّن بَعْدِهِمْ ۖ أَفَتُهْلِكُنَا بِمَا فَعَلَ الْمُبْطِلُونَ (173)

Aboo Hurayrah (may Allah be pleased with him) narrated: “The Messenger of Allah (صلى الله عليه وسلم) said:
“Each child is born upon a sound innate nature. However, his parents make him a Jew or a Christian or a Magian.” Aboo Hurayrah then recited: (This religion is) the original disposition from Allah upon which He originated (Literally: constituted) mankind. There is no altering (the laws of) Allah's creation. That is the most upright religion. Quran 30:30 
فَأَقِمْ وَجْهَكَ لِلدِّينِ حَنِيفًا ۚ فِطْرَتَ اللَّهِ الَّتِي فَطَرَ النَّاسَ عَلَيْهَا ۚ لَا تَبْدِيلَ لِخَلْقِ اللَّهِ ۚ ذَٰلِكَ الدِّينُ الْقَيِّمُ

وَلَٰكِنَّ أَكْثَرَ النَّاسِ لَا يَعْلَمُونَ (30)

Allah, the Exalted, said: Were they created by nothing, or were they themselves the creators? at-Toor: 35

أَمْ خُلِقُوا مِنْ غَيْرِ شَيْءٍ أَمْ هُمُ الْخَالِقُونَ (35)