In The Name of Allaah, The Most Merciful, The Bestower of Mercy.
Imaam Muhammad Ibn Abdul Wahhaab [rahimahullaah] stated in Al-Usool Ath-Thalaatha, “I’lam, Rahimakallaah – Know, may Allah have mercy upon you”.
Shaikh Saaleh al Fawzaan [hafidha-hullaah] stated: “Rahimakallaah” – this is a supplication made for the student of knowledge. The Shaikh [Imam Muhammad ibn Abdul Wahhaab] supplicates for the Mercy of Allaah upon the students of knowledge, that Allaah has mercy upon them. So in this there is gentleness from the teacher towards the student. Indeed he [the teacher] begins with a good word and a righteous supplication [for the student] so that it has an effect and thereby making the student incline towards his teacher with acceptance. But if he began with a harsh statement or a statement not deemed proper, this would make him [i.e. the student] flee.
Therefore, it is obligated on the teacher and the one who calls to Allaah, and the one who enjoins good and forbids evil, that he is gentle with the one he addresses – by way of supplication for him, commendation and soft speech. For indeed, this calls for acceptance [i.e. one’s call to the truth to be accepted by the ones he is calling]. However, as for the Mu’aanid, [the stubborn wilful opposer], indeed this one is to be addressed differently. Allaah [Glorified be He] said: [وَلَا تُجَـٰدِلُوٓاْ أَهۡلَ ٱلۡڪِتَـٰبِ إِلَّا بِٱلَّتِى هِىَ أَحۡسَنُ إِلَّا ٱلَّذِينَ ظَلَمُواْ مِنۡهُمۡۖ – And argue not with the people of the Scripture unless it be in a way that is better, except with such of them as do wrong]. [29:46]
Those who do wrong among the people of the scripture- wilfully opposing and are haughty- these ones are not addressed with that which is better; rather they are addressed with that which will prevent from their [harm and misguidance]. Allaah said:
يَـٰٓأَيُّہَا ٱلنَّبِىُّ جَـٰهِدِ ٱلۡڪُفَّارَ وَٱلۡمُنَـٰفِقِينَ وَٱغۡلُظۡ عَلَيۡہِمۡۚ وَمَأۡوَٮٰهُمۡ جَهَنَّمُۖ وَبِئۡسَ ٱلۡمَصِيرُ
O Prophet (Muhammad)! Strive hard against the disbelievers and the hypocrites, and be harsh against them, their abode is Hell,-and worst indeed is that destination. 9:73
Striving against the hypocrites is not carried out with weapons, rather it is carried out with proofs, statements, refutation against them with harshness that will prevent [them from propagating their misguidance and harm] and to keep the people away from them. Allah said about them [i.e. the hypocrites]: [وَقُل لَّهُمۡ فِىٓ أَنفُسِہِمۡ قَوۡلاَۢ بَلِيغً۬ا – But admonish them, and speak to them an effective word to reach their innerselves] [4:63]
Therefore, there is a specific type of speech that is prescribed for these people because they are wilful opposers and people afflicted with pride. They do not want the truth, rather they want to misguide the people. So they are addressed in a way they deserve. As for the seeker of guidance, this one is addressed with gentleness and mercy. That is because he wants the truth, knowledge and Faa’idah [i.e. that which will benefit him]. [An Excerpt from ‘Sharh Usool Ath-Thalaatha. page13-15. Slightly paraphrased]