All praises belong to Allah, and may His peace and blessings be upon His noble prophet. To proceed;
Science of the Ambiguous in the Qur'an is one of the sciences of the Qur'an that our great predecessors paid a very great attention to . It is reported by Imam Al-Bukhaari that Ibn Abass said: I waited for a year to ask Umar (may Allah be pleased with them both) about the two women who helped one another against the prophet (peace be upon him). It is also narrated by Ikrima that Ibn Abass said: I searched for the name of the one who emigrated (from his home) in the Cause of Allah and His messenger till death overtakes him, I searched for his name for about fourteen years before I found it.
The scholars of Islam say; the aforementioned evidences show how exalted and esteem seeking the knowledge of the ambiguous of the Qur'an.
Science of the ambiguous in the Qur'an refer to the knowledge of gaining the understanding of the ambiguous and unclear words, or sentences of the Qur'an.
There are many reasons which call for ambiguity in the Qur'an. Among them are;
1 . Veneration of the ambiguous by description without mentioning its special meaning such as when Allah says:
وَلَا يَأْتَلِ أُولُو الْفَضْلِ مِنكُمْ وَالسَّعَةِ أَن يُؤْتُوا أُولِي الْقُرْبَىٰ وَالْمَسَاكِينَ وَالْمُهَاجِرِينَ فِي سَبِيلِ اللَّهِ
" Let not those among you who are endued with grace and amplitude of means resolve by oath against helping their kinsmen, those in want, and those who have left their homes in Allah´s cause…"Q24:22.
إِلَّا تَنصُرُوهُ فَقَدْ نَصَرَهُ اللَّهُ إِذْ أَخْرَجَهُ الَّذِينَ كَفَرُوا ثَانِيَ اثْنَيْنِ إِذْ هُمَا فِي الْغَارِ إِذْ يَقُولُ لِصَاحِبِهِ لَا تَحْزَنْ إِنَّ اللَّهَ مَعَنَا
" If you not help him, (it is no matter): for Allah did indeed help him, when the Unbelievers drove him out: he had no more than one companion; they two were in the cave, and he said to his companion, "Have no fear, for Allah is with us "Q9:40. The intended person and the addressee in the two verses is Abu-Bakr, the first caliph of the prophet(peace be upon him).
2 . Vigilance about the general meaning of the ambiguous, so that it will include all its meaning in general instead of stating the special meaning. Allah says:
وَمَن يَخْرُجْ مِن بَيْتِهِ مُهَاجِرًا إِلَى اللَّهِ وَرَسُولِهِ ثُمَّ يُدْرِكْهُ الْمَوْتُ فَقَدْ وَقَعَ أَجْرُهُ عَلَى اللَّهِ
" And whosoever leaves his home as an emigrant unto Allah and His Messenger, and death overtakes him, his reward is then surely incumbent upon Allah." Q9:100. This verse includes whosoever emigrates in the cause of Allah and His messenger, even if it was revealed on a special person.
3 . Intention of hiding the ambiguous meaning in order to persuade and deal with the thing talking about it with full kindness as Allah says:
وَمِنَ النَّاسِ مَن يُعْجِبُكَ قَوْلُهُ فِي الْحَيَاةِ الدُّنْيَا وَيُشْهِدُ اللَّهَ عَلَىٰ مَا فِي قَلْبِهِ وَهُوَ أَلَدُّ الْخِصَامِ
There is the type of man whose speech about this world´s life May dazzle thee, and he calls Allah to witness about what is in his heart; yet is he the most contentious of enemies. Q2:204. This verse was revealed on the case of Al-Akhnas Ibn Shareek who once pledged allegiance to the prophet, but truly in his heart disbelieve to Allah.
4 . Among the reasons is when the meaning of an ambiguous word is well known and there is no necessity for stating the real meaning, like when Allah says :
وَقُلْنَا يَا آدَمُ اسْكُنْ أَنتَ وَزَوْجُكَ الْجَنَّةَ
" And We said: "O Adam! Dwell you and your wife in the Paradise…" Q2:35. Allah, the exalted did not mention her name, Hawau, Adam's wife, because there was no other wife to him except her and her name was well known to every one.
أَلَمْ تَرَ إِلَى الَّذِي حَاجَّ إِبْرَاهِيمَ فِي رَبِّهِ أَنْ آتَاهُ اللَّهُ الْمُلْكَ
" Have you not looked at him who disputed with Ibrahim (Abraham) about his Lord (Allah), because Allah had given him the kingdom?..."Q2:258. In this verse, the disputed person with Ibrahim did not mentioned because he was known and famous.
However, another reason for ambiguous in the Qur'an is when the meaning of the ambiguous is to be explained in other verse, like the verse:
صِرَاطَ الَّذِينَ أَنْعَمْتَ عَلَيْهِمْ غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ
The Way of those on whom You have bestowed Your Grace "
Those on whom Allah have bestowed His grace is explained in other verse while Allah says:
وَمَن يُطِعِ اللَّهَ وَالرَّسُولَ فَأُولَٰئِكَ مَعَ الَّذِينَ أَنْعَمَ اللَّهُ عَلَيْهِم مِّنَ النَّبِيِّينَ وَالصِّدِّيقِينَ وَالشُّهَدَاءِ وَالصَّالِحِينَ ۚ وَحَسُنَ أُولَٰئِكَ رَفِيقًا
" And whoso obeys Allah and the Messenger, then they will be in the company of those on whom Allah has bestowed His Grace, of the Prophets, the Siddiqun (those followers of the Prophets who were first and foremost to believe in them, like Abu Bakr As-Siddiq ), the martyrs, and the righteous. And how excellent these companions are!" Q4:69.
Finally, it should be understood that evidences according to the traditions (Sunnah) of Allah's messenger must interpret the knowledge of the ambiguous in the Qur'an. It should not be interpreted according to one's opinion and whims except by the Sunnah of the prophet (peace be upon him) and his companions.