What is meant here is that anyone who wants to find out about religion from them should argue with them in a manner that is better, as this will be more effective. Allah says:
ادْعُ إِلِى سَبِيلِ رَبِّكَ بِالْحِكْمَةِ وَالْمَوْعِظَةِ الْحَسَنَةِ
(Invite to the way of your Lord with wisdom and fair preaching...) (16:125) And Allah said to Musa and Harun when he sent them to Fir`awn:
فَقُولاَ لَهُ قَوْلاً لَّيِّناً لَّعَلَّهُ يَتَذَكَّرُ أَوْ يَخْشَى
(And speak to him mildly, perhaps he may accept admonition or fear.) (20:44) Allah says here:
إِلاَّ الَّذِينَ ظَلَمُواْ مِنْهُمْ
(except with such of them as do wrong;) meaning, those who turn away from the truth, turning a blind eye to clear evidence, being stubborn and arrogant. In this case you should progress from debate to combat, fighting them in such a way as to deter them from committing aggression against you. Allah says:
لَقَدْ أَرْسَلْنَا رُسُلَنَا بِالْبَيِّنَـتِ وَأَنزَلْنَا مَعَهُمُ الْكِتَـبَ وَالْمِيزَانَ لِيَقُومَ النَّاسُ بِالْقِسْطِ وَأَنزْلْنَا الْحَدِيدَ فِيهِ بَأْسٌ شَدِيدٌ
(Indeed We have sent Our Messengers with clear proofs, and revealed with them the Scripture and the Balance that mankind may keep up justice. And We brought forth iron wherein is mighty power) until: r
إِنَّ اللَّهَ قَوِىٌّ عَزِيزٌ
(Verily, Allah is All-Strong, All-Mighty) (57:25). Jabir said: "We were commanded to strike with the sword whoever opposes the Book of Allah." And His saying:
وَقُولُواْ ءَامَنَّا بِالَّذِى أُنزِلَ إِلَيْنَا وَأُنزِلَ إِلَيْكُمْ
(and say (to them): "We believe in that which has been revealed to us and revealed to you;) means, `if they tell you something which you do not know to be true or false, say to them: We do not hasten to say it is a lie, because it may be true, and we do not hasten to say it is true because it may be false. We believe in it in general, under the condition that it has been revealed and has not been altered or deliberately misinterpreted.' Imam Al-Bukhari, may Allah have mercy on him, recorded that Abu Hurayrah, may Allah be pleased with him, said, "The People of the Book used to read the Tawrah in Hebrew and explain it in Arabic to the Muslims. The Messenger of Allah ﷺ said:
«لَا تُصَدِّقُوا أَهْلَ الْكِتَابِ وَلَا تُكَذِّبُوهُمْ، وَقُولُوا: آمَنَّا بِاللهِ وَمَا أُنْزِلَ إِلَيْنَا وَمَا أُنْزِلَ إِلَيْكُمْ، وَإِلَهُنَا وَإِلَهُكُمْ وَاحِدٌ، وَنَحْنُ لَهُ مُسْلِمُون»
(Do not believe the People of the Book and do not deny them. Say: "We believe in Allah and what has been revealed to us and what has been revealed to you. Our God and your God is One, and to Him we have submitted.")" This Hadith was narrated only by Al-Bukhari. Al-Bukhari recorded that Ibn `Abbas said: "How can you ask the People of the Book about anything, when your Book that was revealed to the Messenger of Allah ﷺ is more recent, you read it pure and uncontaminated, it tells you that the People of the Book altered and changed the Book, that they write the Book with their own hands and then say, `This is from Allah,' to purchace with it a small price Should not the knowledge that you have, prevent you from asking them No, by Allah, we have never seen any of them asking you about what was sent down to you." Al-Bukhari recorded that Humayd bin `Abdur-Rahman heard Mu`awiyah talking to a group of Quraysh in Al-Madinah. He mentioned Ka`b Al-Ahbar, and said: "He was one of the most truthful of those who narrated from the People of the Book, even though we found that some of what he said might be lies." I say, this means that some of what he said could be classified linguistically as lies, but he did not intend to lie, because he was narrating from manuscripts which he thought were good, but they contained fabricated material, because they did not have people who were so conscientious in memorizing the Scriptures by heart as the people of this great Ummah.