Translation of the verse 125 from Surah An-Nahl : Number of verses 128 - - page 281 - Part 14.
Invite (mankind, O Muhammad SAW) to the Way of your Lord (i.e. Islam) with wisdom (i.e. with the Divine Inspiration and the Quran) and fair preaching, and argue with them in a way that is better. Truly, your Lord knows best who has gone astray from His Path, and He is the Best Aware of those who are guided.
Invite to the way of your Lord with wisdom and good instruction, and argue with them in a way that is best. Indeed, your Lord is most knowing of who has strayed from His way, and He is most knowing of who is [rightly] guided.
(16:125) O Prophet invite to the way of your Lord with wisdom and excellent admonition *122 and discuss things with people in the best manner. *123 Your Lord knows best who has gone astray from His Way and He knows best who is rightly guided.
*122) This instruction is very important for those who are engaged in the propagation of Islam. They should always keep in view two things- "wisdom" and "excellent admonition". "Wisdom" implies that one should use discretion in the work of propagation and should not do this blindly like foolish people. Wisdom demands that one should keep in view the intelligence, capability and circumstances of the addressees and convey the Message in accordance with the requirements of the occasion. Moreover, one should refrain from applying one and the same method to each and every person or group but should first diagnose the real disease of the addressee and then cure it by appealing to his head and heart.
"Excellent admonition" implies two things: (1) One should not be content with convincing the addressee with arguments alone but should also appeal to his feelings. Likewise one should not confine oneself merely to arguments in condemning evils and deviations but should try to convince the other of their repugnance that lies embedded in the human nature. One should also warn of the worst consequences of those evils. Besides, one should not only try to convince the addressee rationally of the soundness and excellence of guidance and righteous deeds but should also create in him interest and love for them. (2) Admonition should be administered in such a manner as to show sincere concern for and the welfare of the addressee. Nothing should be said or done to create the impression that the admonisher is looking down upon him and taking pleasure in his own feeling of superiority. On the contrary, he should feel that the admonisher is filled with the strong desire for his reform and welfare.
*123) "Best manner" implies that one should have a sweet tongue, show noble character and give reasonable and appealing arguments, and refrain from indulging in polemics, argumentation and controversies. The one who discusses things with people in the best manner, does not resort to accusations, crooked arguments, taunts, nor makes fun of the opponent in order to defeat him and to win applause for his own superiority in argument. For these things will produce obduracy and obstinacy. In contrast to this, he will try to convince the other in a simple and humble way, and when he feels that the other person has come down to crooked arguments, he will leave him alone lest the other should go further and further astray in his deviation.