The Da'wah to Allaah is an affair that must be carried out, and the Deen has indeed stood upon the Da'wah and Jihaad after beneficial knowledge. The Most High has said:
"By time, all of mankind is in a state of loss, except those who believe, do righteous deeds and advise one another with the truth and with patience." [Sooratul-'Asr]
So what is meant by Eemaan is the knowledge of Allaah the Perfect the Most High, His names and attributes and His worship. And the righteous action is a branch of knowledge, because the action must be built upon knowledge, along with the call to Allaah, the ordering of good and mutual advice between the Muslims, this is what is desired.
However not everyone is best suited to take on such duties. No one undertakes these affairs except the people of knowledge and mature reasoning, because these affairs are heavily important, no one undertakes them except those who are qualified to do so. And from the calamities of today is that the field of Da'wah has become wide, where everyone has entered into it.
So in the name of the Da'wah, perhaps an individual is Jaahil (ignorant), not suited to give Da'wah, so he corrupts more than he rectifies. Due to his eagerness he takes on affairs with hastiness and recklessness and from his action more evil is produced than cure, without having intended its rectification. Rather maybe he is from those who affiliate themselves to the Da'wah and has goals and desires that he calls to and wants to realize them at the expense of the Da'wah and by troubling the minds of the youth, in the name of the Da'wah and earnest concern for the Deen. Rather the person intends the opposite, by way of deviating the youth and driving them away from their communities, from their leaders and their scholars. So he comes to them manifestly by way of advice and Da'wah, like the hypocrites in this Ummah, those who intend evil for the people in the form of goodness…
So consideration is not given to affiliation or the apparent nature of things, rather what is considered are the realities and the results of affairs.
Along with this, it is Waajib to look into those individuals who affiliate themselves to the Da'wah, where did they study? Where did they take their knowledge from? Where did they grow and develop? And what is their Aqeedah? The Most High has said:
"Or is it that they did not recognize their Messenger, so they deny him?" [Soorah Al-Mu'minoon: 69]
So it is Waajib to look into their actions and the effect they have upon the people, and what have they produced from goodness? And what effect have their actions had on rectification? So it is Waajib to study their state of affairs before their statements and outward appearances are relied upon. This affair is a must, specifically in this time, where there are many callers to Fitnah and indeed the Prophet (صلى الله علیه وسلم) described the callers to Fitnah, that they will be a people from ourselves, speaking our language and when the Prophet (صلى الله علیه وسلم) was asked about the trials, he said:
"Callers to the gates of hellfire, whoever obeys them, will be thrown into it."
He (صلى الله علیه وسلم) called them callers, so it is upon us to be aware of this and that we do not gather in the Da'wah everyone and anyone who says "I call to Allaah" and "This Jamaa'ah calls to Allaah", as it is a must to look into the reality of the affair and the reality of the individual and the groups. For indeed Allaah the Perfect the Most High has restricted the Da'wah, to be a Da'wah to Allaah and to His way, the Most High has said:
"Say this is my way, I call to Allaah." [Soorah Yoosuf :108]
This indicates that there are people who call to other than Allaah… Shaykh-ul-Islaam Muhammad ibn ‘Abdul-Wahaab (رحمه الله) said about this Ayah: "Say this is my way, I call to Allah:" in it is sincerity, for indeed many from amongst the people only call to themselves and do not call to Allaah, the Mighty the Majestic."