Providing More Evidence for Islam Does Not Cure Insincerity
Allah سبحانه وتعالى says:
وَلَوْ أَنَّنَا نَزَّلْنَا إِلَيْهِمُ الْمَلَائِكَةَ وَكَلَّمَهُمُ الْمَوْتَىٰ وَحَشَرْنَا عَلَيْهِمْ كُلَّ شَيْءٍ قُبُلًا مَّا كَانُوا لِيُؤْمِنُوا إِلَّا أَن يَشَاءَ اللَّهُ وَلَٰكِنَّ أَكْثَرَهُمْ يَجْهَلُونَ
And even if We had sent down to them the angels [with the message] and the dead spoke to them [of it], and We gathered together every [created] thing in front of them, they would not believe unless Allah should will. But most of them, [of that], are ignorant. [6:111]
At-Tabari said that most of these ignorant mushrikun:
يَحْسَبُونَ أَنَّ الْإِيمَانَ إِلَيْهِمْ، وَالْكُفْرَ بِأَيْدِيهِمْ، مَتَّى شَاءُوا آمَنُوا، وَمَتَّى شَاءُوا كَفَرُوا. وَلَيْسَ ذَلِكَ كَذَلِكَ
“Think that they are entitled to Iman and that kufr is under their control; that they could believe and disbelieve whenever they willed. However, that is not the case.”
Ar-Razi said:
أنه لا فائدة في إنزال الآيات بعد الآيات وإظهار المعجزات بعد المعجزات، بل المعجزة الواحدة لا بد منها ليتميز الصادق عن الكاذب، فأما الزيادة عليها فتحكم محض ولا حاجة إليه وإلا فلهم أن يطلبوا بعد ظهور المعجزة الثانية ثالثة، وبعد الثالثة رابعة،
“There is no benefit in revealing signs and displaying miracles after they have already been sent and displayed. Rather, one miracle suffices in distinguishing between the truthful person and a liar. To add [more miracles and signs] is purely capricious and unnecessary, for they (i.e., the mushrikun) would only end up asking for a third miracle after the second, and third after the fourth, etc.”
This ayah is important for Muslims, especially du’at and apologists, to bear in mind when giving da’wah. Your inability to convince and convert non-Muslims does not mean that the evidence you are offering for Islam is lacking. Your presentation and defense of it may be, however, also not necessarily so. Evidence does not cure insincerity. Evidence does not remedy a heart that does not desire to turn to God’s truth. A person needs to desire to be guided, and it is only such a person who would be receptive to the evidence for Islam. Otherwise, it does not matter how many arguments you offer; they would not penetrate hearts that are closed off to the truth it deems unappealing.
Iman in Islam is not mere cognitive belief but rather mental acceptance and submission as well. Evidence alone does not sway rebellious hearts.
وَلَوْ أَنَّنَا نزلْنَا إِلَيْهِمُ الْمَلائِكَةَ وَكَلَّمَهُمُ الْمَوْتَى وَحَشَرْنَا عَلَيْهِمْ كُلَّ شَيْءٍ قُبُلا مَا كَانُوا لِيُؤْمِنُوا إِلا أَنْ يَشَاءَ اللَّهُ وَلَكِنَّ أَكْثَرَهُمْ يَجْهَلُونَ
And even if We had sent down to them the angels [with the message] and the dead spoke to them [of it] and We gathered together every [created] thing in front of them, they would not believe unless Allah should will. But most of them, [of that], are ignorant. [6:111]
وَلَوۡ فَتَحۡنَا عَلَیۡهِم بَابࣰا مِّنَ ٱلسَّمَاۤءِ فَظَلُّوا۟ فِیهِ یَعۡرُجُونَ ١٤ لَقَالُوۤا۟ إِنَّمَا سُكِّرَتۡ أَبۡصَـٰرُنَا بَلۡ نَحۡنُ قَوۡمࣱ مَّسۡحُورُونَ ١
And even if We opened for them a gate to heaven, through which they continued to ascend, still they would say, “Our eyes have truly been dazzled! In fact, we must have been bewitched.” [15:14-15]