باب مَنِ اسْتَحْيَا فَأَمَرَ غَيْرَهُ بِالسُّؤَالِ
Chapter 51 : That who felt shy (to ask something) and then requested another person to ask on his behalf.

Purpose of Tarjamatul Baab
Here Imam Bukhari (RA) wants to say that one should always try to learn religious knowledge from learned scholars. If one feels shy to ask questions, he should request someone else to ask on his behalf as was done by Hadhrat Ali (RA).

Hadith No. 130
حَدَّثَنَا مُسَدَّدٌ قَالَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ دَاوُدَ عَنِ الأَعْمَشِ عَنْ مُنْذِرٍ الثَّوْرِىِّ عَنْ مُحَمَّدٍ ابْنِ الْحَنَفِيَّةِ عَنْ عَلِىٍّ قَالَ كُنْتُ رَجُلاً مَذَّاءً فَأَمَرْتُ الْمِقْدَادَ أَنْ يَسْأَلَ النَّبِىَّ - صلى الله عليه وسلم - فَسَأَلَهُ فَقَالَ فِيهِ الْوُضُوءُ

Narrated 'Ali (RA)
I used to get the emotional urethral discharge frequently so I requested Al-Miqdad to ask the Prophet about it. Al-Miqdad asked him and he replied, "One has to perform ablution (after it)."

Comments
This Hadith shows that shyness should not become an impediment to learn. It also shows the eagerness of Hadhrat Ali (RA) to learn and also teaches that one can learn such things indirectly.

باب ذِكْرِ الْعِلْمِ وَالْفُتْيَا فِى الْمَسْجِدِ .
Chapter 52 : The mentioning of religious knowledge and juristic verdicts in Musjid.
Purpose of Tarjamatul Baab
The Musjids have been basically built for prayers like Salah, Zikr and recitation of Al-Qur'an. Here Imam Bukhari clears a debatable issue i.e., is it permissible to discuss and learn about religion in Musjid? By quoting this Hadith he answers this question in affirmative.

Hadith No. 131
حَدَّثَنِى قُتَيْبَةُ بْنُ سَعِيدٍ قَالَ حَدَّثَنَا اللَّيْثُ بْنُ سَعْدٍ قَالَ حَدَّثَنَا نَافِعٌ مَوْلَى عَبْدِ اللَّهِ بْنِ عُمَرَ بْنِ الْخَطَّابِ عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ . أَنَّ رَجُلاً قَامَ فِى الْمَسْجِدِ فَقَالَ يَا رَسُولَ اللَّهِ ، مِنْ أَيْنَ تَأْمُرُنَا أَنْ نُهِلَّ فَقَالَ رَسُولُ اللَّهِ - صلى الله عليه وسلم - يُهِلُّ أَهْلُ الْمَدِينَةِ مِنْ ذِى الْحُلَيْفَةِ ، وَيُهِلُّ أَهْلُ الشَّأْمِ مِنَ الْجُحْفَةِ ، وَيُهِلُّ أَهْلُ نَجْدٍ مِنْ قَرْنٍ . وَقَالَ ابْنُ عُمَرَ وَيَزْعُمُونَ أَنَّ رَسُولَ اللَّهِ - صلى الله عليه وسلم - قَالَ وَيُهِلُّ أَهْلُ الْيَمَنِ مِنْ يَلَمْلَمَ . وَكَانَ ابْنُ عُمَرَ يَقُولُ لَمْ أَفْقَهْ هَذِهِ مِنْ رَسُولِ اللَّهِ - صلى الله عليه وسلم

Narrated Nafi (RA)
'Abdullah bin 'Umar said: "A man got up in the Musjid and said: O Allah's Apostle 'At which place you order us that we should assume the Ihram?' Allah's Apostle replied, 'The residents of Madina should assume the Ihram from Dhil-Hulaifa, the people of Syria from Al-Ju,hfa and the people of Najd from Qarn." Ibn 'Umar further said, "The people consider that Allah's Apostle had also said, 'The residents of Yemen should assume Ihram from Yalamlam.' " Ibn 'Umar used to say, "I do not: remember whether Allah's Apostle had said the last statement or not?"

باب مَنْ أَجَابَ السَّائِلَ بِأَكْثَرَ مِمَّا سَأَلَهُ
Chapter 53 : That who answered the questioner more than what he was asked for.

Purpose of Tarjamatul Baab
Sometimes the scholar should answer in detail rather than in brief.

Hadith No. 132
حَدَّثَنَا آدَمُ قَالَ حَدَّثَنَا ابْنُ أَبِى ذِئْبٍ عَنْ نَافِعٍ عَنِ ابْنِ عُمَرَ عَنِ النَّبِىِّ - صلى الله عليه وسلم - . وَعَنِ الزُّهْرِىِّ عَنْ سَالِمٍ عَنِ ابْنِ عُمَرَ عَنِ النَّبِىِّ - صلى الله عليه وسلم - أَنَّ رَجُلاً سَأَلَهُ مَا يَلْبَسُ الْمُحْرِمُ فَقَالَ لاَ يَلْبَسِ الْقَمِيصَ وَلاَ الْعِمَامَةَ وَلاَ السَّرَاوِيلَ وَلاَ الْبُرْنُسَ وَلاَ ثَوْبًا مَسَّهُ الْوَرْسُ أَوِ الزَّعْفَرَانُ ، فَإِنْ لَمْ يَجِدِ النَّعْلَيْنِ فَلْيَلْبَسِ الْخُفَّيْنِ وَلْيَقْطَعْهُمَا حَتَّى يَكُونَا تَحْتَ الْكَعْبَيْنِ

Narrated Ibn 'Umar (RA)
A man asked the Prophet : "What (kinds of clothes) should a Muhrim (a Muslim intending to perform 'Umra or Hajj) wear? He replied, "He should not
wear a shirt, a turban, trousers, a head cloak or garment scented with saffron or al-wars (kinds of perfumes). And if he has no slippers, then he can use Khuffs (leather socks) but the socks should be cut short so as to make the ankles bare."

Al-Hamdu Lillah, by the grace and blessings of Allah Subhaanahu wa Ta'ala,
Kitab-ul-Ilm has ended.

erse 145

وَلَئِنْ أَتَيْتَ الَّذِينَ أُوتُوا الْكِتَابَ بِكُلِّ آيَةٍ مَا تَبِعُوا قِبْلَتَكَ وَمَا أَنْتَ بِتَابِعٍ قِبْلَتَهُمْ وَمَا بَعْضُهُمْ بِتَابِعٍ قِبْلَةَ بَعْضٍ وَلَئِنِ اتَّبَعْتَ أَهْوَاءَهُمْ مِنْ بَعْدِ مَا جَاءَكَ مِنَ الْعِلْمِ إِنَّكَ إِذًا لَمِنَ الظَّالِمِينَ ()
And even if you bring every sign to those who have been given the Book, they would not follow your Qiblah. And you are not to follow their Qiblah, nor are they to follow each other's Qiblah. And if you were to follow their desires after the knowledge that has come to you, you will then certainly be among the unjust.
In continuing the discussion on the subject of the Qiblah, or the divinely-ordained orientation, the present verse provides yet another instance of the maliciousness of the People of the Book. It is not that they demand solid and convincing arguments in order to be able to accept the new injunction with regard to the Qiblah: it is sheer stubbornness which does not allow them to give their assent, and no proof in the world, declares the Holy Qur'an, is ever going to satisfy them. In fact, their two groups display an equal malice even towards each other - the Jews have adopted the Baytul-Maqdis as their Qiblah, while the Christians have chosen the East, and each group rejects the Qiblah of the other. On the other hand, the Holy Prophet (Sallallahu Alaihi Wasallam) cannot accept either of these two orientations, for the new Qiblah of the Muslims - the Baytullah - has been instituted by a divine commandment, and is never going to be abrogated. So, there is no likelihood of an agreement between the People of the Book and the Muslims in this, matter. The Baytul-Maqdis, no doubt, had once been instituted by a divine commandment, but that commandment has now been abrogated. Anyone who follows an abrogated injunction, and ignores the new injunction which has replaced the earlier one, is actually disobeying Allah, and acting upon his individual opinion and personal desire. Naturally, it is impossible for the Holy Prophet (Sallallahu Alaihi Wasallam) to follow the desires of the People of the Book. But, supposing for the sake of supposition, were he to do so even after having received a definite injunction through the Wahy (Revelation), he would be counted among the unjust - that is, among those who disobey divine commandments. Such a situation, however, can never arise. Being a prophet, he is essentially sinless, and as such cannot possibly be among the unjust. From this principle it logically follows that it is impossible for him to favour the desires of the People of the Book, and to accept their Qiblah as his own.
Let us make it quite clear that this warning is outwardly addressed to the Holy Prophet (Sallallahu Alaihi Wasallam), but is, in fact, intended for his Ummah, which is being asked to realize fully the gravity of the sin of ignoring or disobeying the injunction which has finally established the Baytullah as the Qiblah of the Muslims.
As for the phrase, و ما أنت بتابع : "You are not to follow their Qiblah", it is meant to declare that the Baytullah shall now stay as the Qiblah upto the end of the world. Thus, the declaration refutes the scoffing allegation of the People of the Book that there was no stability in the Islamic injunctions, and that the Muslims might again adopt the Baytul-Maqdis as their Qiblah. (Al-Bahr al-Muhit)

Verse 146-147
الَّذِينَ آتَيْنَاهُمُ الْكِتَابَ يَعْرِفُونَهُ كَمَا يَعْرِفُونَ أَبْنَاءَهُمْ وَإِنَّ فَرِيقًا مِنْهُمْ لَيَكْتُمُونَ الْحَقَّ وَهُمْ يَعْلَمُونَ () الْحَقُّ مِنْ رَبِّكَ فَلَا تَكُونَنَّ مِنَ الْمُمْتَرِينَ ()
Those whom We have given the Book recognize him (The Holy Prophet) as they recognize their own sons. And, in fact, a group of them does conceal the truth while they know. The truth is from your Lord. So, never be among those who doubt."

Verses 144 and 145 have told us how the People of the Book knew in their hearts that a divine commandment itself had instituted the Baytullah as the Qiblah of the Muslims, and yet denied this fact in public. Now, the two present verses show that their conduct towards the Holy Prophet (Sallallahu Alaihi Wasallam) was equally dishonest and malicious.
The Torah and the Evangile had already foretold the coming of the Holy Prophet (Sallallahu Alaihi Wasallam) and set down the signs and indications which should help the people to recognize him. On the basis of the irrefutable evidence provided by their own Sacred Books, the Jews and the Christians knew him to be the promised Last Prophet (Sallallahu Alaihi Wasallam), but many of them refused to acknowledge him as such out of sheer obstinacy.
Let us add a word or two in order to explain the simile employed here by the Holy Qur'an - that of man recognizing his own son without any doubt or ambiguity. As everyone knows, in bringing two terms into comparison with each other, a simile does not involve in this analogy all the aspects of these two terms, but only those which should be relevant to the occasion. So, in considering the present simile one should not allow one's imagination to roam far afield, and bring under discussion even those cases which happen to be illegitimate. For, the present simile intends to make a very simple and obvious point - since the son grows from infancy to manhood normally under the eyes of his parents, his face or general appearance is quite sufficient for his father to recognize him without any doubt or hesitation. The Jews and the Christians enjoyed the same kind of facility - or even certainty - in being able to recognize the Last Prophet (Sallallahu Alaihi Wasallam). So, to persist in denying him was as dishonest as refusing to recognize one's own son should normally be.
And it was just this kind of gross dishonesty that the People of the Book were indulging in. Some of them, while denying the truth themselves, even tried to keep it concealed from others, although they knew fully well that this particular truth (that is to say, the new injunction with regard to the Qiblah) had been established by Revelation from Allah Himself.
The phrase, "The Truth is from your Lord", can also be interpreted in a general sense as providing a definition of the nature of truth -namely, that alone is truth which comes from Allah. One who has understood this fact can never allow himself to be in doubt with regard to this particular truth or to any other which has been revealed to a prophet by Allah.