A’lee bin Abee Taalib , may Allah be pleased with him, said:
“You should preach to the people in a way that they can easily understand, would you like that Allah and His Messenger, sallallahu alaihi wassallam, be denied?” (Darussalam Translation).
Abdullah bin Mas’ood, may Allah be pleased with him, said:
“You do not address the people with a speech which exceeds their level of comprehension, except that it will be for some of them a tribulation “
Abu Qilaabah Abdullah bin Zayd al-Jarmee, may Allah have mercy upon him, said:
“Do not address with a speech he who does not understand it, for verily (addressing) he who does not understand will only be harmed by it and will not be a benefit to him”
These narrations are found in the book ‘Jaam’i bayaan al-I’lm wa fadlihi’ by al-Imaam Ibn Abdul Barr, may Allah have mercy upon him.
Some may object to the aforementioned email from the point of view that some people no matter how you address them they will always misunderstand due to a sickness in their heart or due to a reason which only Allah is aware of, we ask Allah as-saalamah (to frees us from that affliction), so yes one should resemble al-Imaam Muqbil, may Allah have mercy upon him, when he used to say which is in poetry form:
علي نحت القوافي من معادنها وما علي إذا لم تفهم البقر
This basically means that it is only upon you to strive to make your speech clear and it is not upon you if the cow (a metaphor for an imprudent person) does not understand.
Reference: al-Mahfoothaat ash-Shi’riyyah ,print daarul aathaar.
Likewise, this is similar to a poetry which has been recited by Ibn Fadl, may Allah have mercy upon him, when he was defending Shaykul Islaam bin Taymiyyah from those who deliberately misunderstood his speech, as found in the book ‘Ash-Shahaadatuz Zakiyyah’ by Ibn Mar’ee
~ Abu Fajr AbdulFattaah bin Uthman