The Messenger knew his people more than they knew themselves. Like Abu Dharr, 'Amr ibn 'Abatha was a bedouin. He came to Makka and, meeting the Messenger, asked rudely: "What are you?" The Messenger replied very gently: "A Prophet of God." Such gentleness caused 'Amr to kneel down and declare: "I will follow you from now on, O Messenger." The Messenger did not want 'Amr to stay in Makka, for he would be unable to endure the torments inflicted upon the believers. So he told him: "Return to your tribe, and preach Islam among them. When you hear that I am victorious, come and join us."
Years later, 'Amr came to Madina's mosque and asked the Messenger: "Do you recognize me, O Messenger?" The Messenger, who had an extraordinarily strong and keen memory (another dimension of his Prophethood) answered promptly: "Aren't you the one who came to me in Makka? I sent you back to your tribe and told you to join us when you heard that I was victorious." 
I mentioned the case of Julaybib earlier. After the moral lesson of the Messenger, Julaybib became an honest, chaste young man. Upon the Messenger's request, a noble family gave him their daughter in marriage. Shortly afterwards, Julaybib took part in a battle and, after killing 7 enemy soldiers, was martyred. When his corpse was brought to the Messenger, he put his head on Julaybib's knees and said: "O God, this one is of me, and I am of him." He had discovered Julaybib's essential virtue and foreseen his future service for Islam.
The conquest of Khaybar was an occasion for the Messenger to demonstrate his unique ability to recognize each Muslim's potential, skills, and shortcomings. When the siege was prolonged, he declared: "Tomorrow I will hand the standard to one who loves God and His Messenger and is loved by them." This was a great honor, and all Companions earnestly hoped for it. He gave it to 'Ali, despite his youth, because of his great military and leadership skills. He took the standard and conquered the formidable stronghold of Khaybar.
Whoever the Messenger gave a job to performed it successfully. For example, he described Khalid ibn Walid as "a sword of God"; Khalid was never defeated. Besides such great soldiers and invincible commanders as Qa'qa'a, Hamza, and Sa'd, the Messenger made 'Usama ibn Zayd commander over a great army containing such leading Muslims as Abu Bakr, 'Umar, 'Uthman, Talha, and Sa'd ibn Abi Waqqas. 'Usama was the approximately 17-year-old son of Zayd, the Messenger's black emancipated slave. His father had commanded the Muslim army at Mu'ta against the Byzantines, and was martyred.
The Messenger was 25 when he married Khadija bint Khuwaylid, a widow 15 years his senior. He did not marry another woman until her death in the tenth year of his Prophethood. All of his subsequent marriages, after the age of 53, were directly related to his mission. One important reason for this was that each wife had a different character and temperament, and so could convey to other Muslim women Islam's rules for women. Each one served as a guide and teacher for womanhood. Even such leading figures in subsequent generations as Masruq, Tawus ibn Kaysan, and Ata' ibn Rabah benefited considerably from them. The science of hadith is especially indebted to 'A'isha, who related more than 5,000 Traditions from the Messenger and was a great jurist.
Subsequent events proved how wise and apt were the Messenger's the choices, not least in the matter of marriage.