From this starting point, it becomes obligatory that the Muslim adorn and beautify himself with good character whether he is a daa`iya or not. Because morality is one of the goals of the Muhammadan mission that Allah blessed the entirety of mankind with, and He specified that the believers alone posses a special kind of it. This He did, when He guided them through it to the straight path, purified their souls, and taught them that which they did not know.
“He it is Who raised among the inhabitants of Makkah a Messenger from among themselves, who recites to them His communications and purifies them, and teaches them the Book and the Wisdom, although they were before certainly in manifest error."
The purification [tazkiyah] that is mentioned in this noble verse includes the purification of the nafs [self], exalting it through high morals and cleansing it from wickedness. In this verse as in the previous hadeeth, morality appears not only to be one of the goals of the Muhammadan mission, but one of its most distinctive goals. And if embellishing oneself with moral excellence is obligatory for the Muslims... then what about the daa'iya who carries the banner of dawa and calls the people to it? Surely the popular view is rather inclined towards him, mistakes are rather expected from him, and criticism is stronger against him. His dawa has to be a reflection of how he is. That is why possessing moral integrity is obligatory and essential, for carrying out properly that which Allah burdened him with... as the poet said: "Thanks for your favor of carrying our burden! For because of you, we are certain of calamity." It is essential in order to safeguard the dawa and it's people from the tongues of the biased, the pens of it's opponents, and the conjecture of the heedless and hasty!
If I were to discuss each of the morals, this would be a long discussion and still not be enough. r have in front of me a large collection of assorted books on morality, some of which are: "The Characteristics of the Prophet" by Shaykh al- Asbahaaniy, "The Noble Characteristics" by aI-Tabaraaniy, and al- Karaa'etiy, "The Morals and Biographies" by Ibn Hazm, "Constitution of Morals in the Qur'an" by Muhammad 'Abdullah Darraaz... etc.
So this message, my dear brothers, is not a research into morality and its philosophies, but an illustration along with many evidences, of a host of worthy characteristics which I felt were of great importance for the daa`iya. I have commented in some important areas, and left the rest which is accessible through reference for he who desires it.