Muslims at the time of messenger Muhammad (PBUH) were coming from a war. The sky was clear and the sun was very strong in a hot day. Suddenly a single cloud appeared and covered the sun protecting them for long time. It was a miracle for Muslims at that time, for the hypocrites it was a cloud and passed by. God gave us alot of signs. That I wish we do not look at them and say a cloud and passed by:
1- The creation:
2:164 Behold! in the creation of the heavens and the earth; in the alternation of the night and the day; in the sailing of the ships through the ocean for the profit of mankind; in the rain which Allah Sends down from the skies, and the life which He gives therewith to an earth that is dead; in the beasts of all kinds that He scatters through the earth; in the change of the winds, and the clouds which they Trail like their slaves between the sky and the earth;- (Here) indeed are signs for a people that are wise. إِنَّ فِي خَلْقِ السَّمَاوَاتِ وَالأَرْضِ وَاخْتِلاَفِ اللَّيْلِ وَالنَّهَارِ وَالْفُلْكِ الَّتِي تَجْرِي فِي الْبَحْرِ بِمَا يَنفَعُ النَّاسَ وَمَا أَنزَلَ اللّهُ مِنَ السَّمَاء مِن مَّاء فَأَحْيَا بِهِ الأرْضَ بَعْدَ مَوْتِهَا وَبَثَّ فِيهَا مِن كُلِّ دَآبَّةٍ وَتَصْرِيفِ الرِّيَاحِ وَالسَّحَابِ الْمُسَخِّرِ بَيْنَ السَّمَاء وَالأَرْضِ لآيَاتٍ لِّقَوْمٍ يَعْقِلُونَ
2- Our failure to prove existence from non-existence. We did not see the creation to disprove the Bible and Quran:
18:51 I called them not to witness the creation of the heavens and the earth, nor (even) their own creation: nor is it for Me to take as helpers such as lead (men) astray!
مَا أَشْهَدتُّهُمْ خَلْقَ السَّمَاوَاتِ وَالْأَرْضِ وَلَا خَلْقَ أَنفُسِهِمْ وَمَا كُنتُ مُتَّخِذَ الْمُضِلِّينَ عَضُدًا
3- The good and evil:
4-21:35 Every soul shall have a taste of death: and We test you by evil and by good by way of trial. to Us must ye return.
كُلُّ نَفْسٍ ذَائِقَةُ الْمَوْتِ وَنَبْلُوكُم بِالشَّرِّ وَالْخَيْرِ فِتْنَةً وَإِلَيْنَا تُرْجَعُونَ
4- The scientific miracles of the Quran: see my blog, one here is self identity from finger print.
Yes, We are able to put together in perfect order the very tips of his fingers. (Qur'an, 75:4)
5-The linguistic miracles of the Quran:
36:69 We have not instructed the (Prophet) in poetry, nor is it meet for him: this is no less than a Message and a Qur'an making things clear: وَمَا عَلَّمْنَاهُ الشِّعْرَ وَمَا يَنبَغِي لَهُ إِنْ هُوَ إِلَّا ذِكْرٌ وَقُرْآنٌ مُّبِينٌ
6-The personality of the messenger Muhammad (PBUH): was very honest and fears God. The worst lie is to lie against God:
6:21 Who doth more wrong than he who inventeth a lie against Allah or rejecteth His signs? But verily the wrong-doers never shall prosper.
وَمَنْ أَظْلَمُ مِمَّنِ افْتَرَى عَلَى اللّهِ كَذِبًا أَوْ كَذَّبَ بِآيَاتِهِ إِنَّهُ لاَ يُفْلِحُ الظَّالِمُونَ
7-Quran in large part agrees with the old and new testament and confirms the stories in the bible:
2:41 And believe in what I reveal, confirming the revelation which is with you (Jews and Christians), and be not the first to reject Faith therein, nor sell My signs for a small price; and fear Me, and Me alone.
وَآمِنُواْ بِمَا أَنزَلْتُ مُصَدِّقاً لِّمَا مَعَكُمْ وَلاَ تَكُونُواْ أَوَّلَ كَافِرٍ بِهِ وَلاَ تَشْتَرُواْ بِآيَاتِي ثَمَناً قَلِيلاً وَإِيَّايَ فَاتَّقُونِ
8-The miracle of the Quran supersedes the physical miracles of Moses and Jesus since it is continues and for all people. In fact the disbelievers dealt with these signs as sorcery.
27:13 But when Our signs came to them, that should have opened their eyes, they said: "This is sorcery manifest!" فَلَمَّا جَاءتْهُمْ آيَاتُنَا مُبْصِرَةً قَالُوا هَذَا سِحْرٌ
27:14 And they rejected those signs in iniquity and arrogance, though their souls were convinced thereof: so see what was the end of those who acted corruptly!
وَجَحَدُوا بِهَا وَاسْتَيْقَنَتْهَا أَنفُسُهُمْ ظُلْمًا وَعُلُوًّا فَانظُرْ كَيْفَ كَانَ عَاقِبَةُ الْمُفْسِدِينَ
7:132 They said (to Moses): "Whatever be the signs thou bringest, to work therewith thy sorcery on us, we shall never believe in thee.
وَقَالُواْ مَهْمَا تَأْتِنَا بِهِ مِن آيَةٍ لِّتَسْحَرَنَا بِهَا فَمَا نَحْنُ لَكَ بِمُؤْمِنِينَ
9-God gives the signs he wants to and to ask to see God, the angels or his wrath (like Noah flood) are all late signs. I would rather stick to the above signs.
6:158 Are they waiting to see if the angels come to them, or thy Lord (Himself), or certain of the signs of thy Lord! the day that certain of the signs of thy Lord do come, no good will it do to a soul to believe in them then if it believed not before nor earned righteousness through its faith. Say: "Wait ye: we too are waiting."
هَلْ يَنظُرُونَ إِلاَّ أَن تَأْتِيهُمُ الْمَلآئِكَةُ أَوْ يَأْتِيَ رَبُّكَ أَوْ يَأْتِيَ بَعْضُ آيَاتِ رَبِّكَ يَوْمَ يَأْتِي بَعْضُ آيَاتِ رَبِّكَ لاَ يَنفَعُ نَفْسًا إِيمَانُهَا لَمْ تَكُنْ آمَنَتْ مِن قَبْلُ أَوْ كَسَبَتْ فِي إِيمَانِهَا خَيْرًا قُلِ انتَظِرُواْ إِنَّا مُنتَظِرُونَ
So I tell to those who would say a cloud and passed by be more wise.
Those who continue to reject God's signs are choosing hell over heaven.
2:39 "But those who reject Faith and belie Our signs, they shall be companions of the Fire; they shall abide therein."
وَالَّذِينَ كَفَرواْ وَكَذَّبُواْ بِآيَاتِنَا أُولَـئِكَ أَصْحَابُ النَّارِ هُمْ فِيهَا خَالِدُونَ
It is important to have faith and the more strong the faith the better off you are. To submit to Islam (mental) can be even started with zero faith (spiritual). Even very faithful Muslims would ask God to die on the submission of Islam. So submission gives you the ground that you build your faith on. Submission means even if I get doubts sometimes, I would continue to declare my faith since I have overwhelming signs of God existence.