The Outstanding Perseverance of Rasulullah SAW, when Inviting Hakam bin Kaysaan to Islam Miqdaad bin Amr narrates that when he took Hakam bin Kaysaan prisoner (during one of the battles), his commander wanted Hakam executed. However, he (Miqdaad RA )managed to persuade his commander not to execute Hakam but to rather take him to Rasulullah SAW.
When they brought him to Rasulullah SAW, the noble Rasulullah SAW started inviting him to accept Islam and spent a long time speaking to him. After some time, Saidina Umar RA said, "0 Rasulullah!!For what reason are you talking to him so much? By Allah! He shall never accept Islaam! Allow me to execute him so that he may reach his destination in Jahannam!"
However, Rasulullah SAW paid no attention to Saidina Umar RA (and continued speaking) until Hakam accepted Islam. Saidina Umar RA says, "When I saw Hakam accept Islaam, I was surrounded by thoughts of the past and future. I chided myself for addressing Rasulullaah SAW concerning a matter about which he had more knowledge than me. I then told myself that I had done so only for the welfare of Allah SWT and His Rasul SAW.
Saidina Umar RA said, "Hakam became a Muslim and by Allah SWT, also he was an excellent Muslim who fought for the pleasure of Allah SWT until he was martyred at Bir Ma'una. Rasulullaah SAW was pleased with him and he has entered the gardens of Jannah."
In a narration of Zuhri, Hakam asked Rasulullaah SAW, "What is Islaam?" Rasulullah SAW replied, "That you worship Allaah Alone Who has no partner and that you testify that Muhammad is Allah's servant and Rasul." Hakam then said, "I accept Islaam." Rasulullah SAW then turned to the Sahabah RA and said, "Had I listened to you just now and killed him, he would have entered the fire of Jahannam."