There is nothing wrong in Shari`ah regarding holding dialogues with the People of the Book about questions of belief. But this is to be done by a person who is knowledgeable about the teachings and principles of Islam as well as about the beliefs and different creeds of the People of the Book. This person should do this for Almighty Allah’s sake and adhere to the proprieties that should be followed while using online messengers. May Almighty Allah guide those people to the right path.
Sheikh Ahmad Bin Hamad Al-Khalili, mufti of the Sultanate of Oman, states: Islam is a tolerant religion that opens the way for reasonable dialogues with others. Allah Almighty says:

“And argue not with the People of the Scripture unless it be in (a way) that is better, save with such of them as do wrong; and say: We believe in that which hath been revealed unto us and revealed unto you; our Allah and your Allah is One, and unto Him we surrender” (Al-`Ankabut: 46).
According to this verse, discussing with the People of the Book in a reasonable and convincing way may be a cause to guiding to the right path those among them whom Almighty Allah wills to guide. But it should be kept in mind that he who holds a dialogue with them must be a knowledgeable person who is well aware of the different aspects of the subject he is handling with them, so that he may achieve positive results. Should a person who is not knowledgeable hold a dialogue with them, the result would be negative.

The eminent Muslim scholar Sheikh Yusuf Al-Qaradawi, states: Muslims do not hold dialogues with the People of the Book so that the People of the Book may be pleased with them. Rather, they enter into dialogues with one another so that they may find a common ground upon which they can coexist and cooperate without bearing grudges against one another. Allah Almighty says: “And argue not with the People of the Scripture unless it be in (a way) that is better, save with such of them as do wrong; and say: We believe in that which hath been revealed unto us and revealed unto you; our Allah and your Allah is One, and unto Him we surrender” (Al-`Ankabut:46). Mind that in this verse Allah Almighty orders the Muslims to argue with the People of the Book “in (a way) that is better.”

He Almighty has also clarified the method for calling to Islam by saying: “Call to the way of your Lord with wisdom and goodly exhortation, and have disputations with them in the best manner; surely your Lord best knows those who go astray from His path, and He knows best those who follow the right way” (An-Nahl: 125).
According to this verse, calling to Islam is to be done with wisdom and goodly exhortation, for exhortation appeals to those who have wise hearts and submissively follow the right path. But those who are stubborn and not easily convinced need to be argued with in a way that is more than good exhortation; that is why Almighty Allah says “and have disputations with them in the best manner.” This is to say, if there are two methods before a Muslim to follow while holding a dialogue with some People of the Book, he is to choose the better of them so that the dialogue be constructive and there be no grudges borne on both sides.
Allah Almighty has ordered His Prophet (peace and blessings be upon him) to say while arguing with the disbelievers “Certain it is that either we or ye are on right guidance or in manifest error!” (Saba’: 24). Of course, this argument on the part of the Prophet (peace and blessings be upon him) does not mean that he (peace and blessings be upon him) doubted that he was on right guidance. But it was a way of gradually calling them to adopt his point of view.
The same goes also for the verse “Say: You will not be questioned as to what we are guilty of, nor shall we be questioned as to what you do” (Saba’: 25). One may say that the parallelism between the two parts of this verse would have dictated that it be “You will not be questioned as to what we are guilty of, nor will we be questioned as to what you are guilty of.” But Allah ordered the Prophet (peace and blessings be upon him) to say this so as not to accuse them of anything guilty so that they would not turn away from listening to him.
Based on the above-mentioned verse “And argue not with the People of the Scripture unless it be in (a way) that is better”, the Qur’an urges the Muslims to bear in mind the common ground that exists between them and the People of the Book when it comes to entering in a dialogue with them. They are not to concentrate on the points of difference between the two sides.
Again, it should be quite clear that Muslims do not hold dialogues with the People of the Book so that the latter may be pleased with them. It is established that the People of the Book would not be pleased with Muslims until the latter follow the former’s way. Hence, entering into dialogues with them should, rather, aim at finding a common ground that may help both sides to cooperate in combating atheism, dissoluteness, aggression, and so on. This applies, for instance, to the Muslims’ attempt to mobilize the support of the Christians regarding issues of concern to both sides such as combating the Zionist aggression against both the Muslim and Christian Palestinians and the Israeli violations against Al-Aqsa Mosque and Al-Quds.