Khalid's ingenuity impressed the Roman officers and commanders so much so that Jerjah, a Roman commander, asked Khalid to show himself during a rest in the fighting. When they met, the Roman commander asked him, Khalid, tell me the truth and do not lie, for the freeman doesn't lie. Did Allah send down on your Prophet a heavenly sword and he gave it to you, so that it enables you to kill anyone who comes within its sweep?' Khalid answered, No.' The man exclaimed, Then why do they call you the Sword of Allah?' Khalid explained, Allah sent His Prophet to us. Some of us believed in him and others disbelieved in him. I was among the disbelievers until Allah guided my heart to Islam and to His Prophet SAW and I gave him my allegiance. Therefore, the Prophet supplicated Allah for me and said, You are the Sword of Allah.'' The Roman commander asked, What do you invite people to?' Khalid answered, We invite people to monotheism and to Islam.' He asked, Does anyone who submits himself to Islam have the same reward as you?' Khalid answered, Yes, and even better.' Jerjah exclaimed, How, when you embraced Islam before he did?'
Khalid answered, We lived with the Prophet SAW and saw with our own eyes his signs and miracles. Now anyone who had the chance to see what we saw and hear what we heard was expected to submit himself to Islam sooner or later. As for you who did not see or hear him, if despite this you believe in him and in the unseen, you will find better and greater reward if you purify your conscience and intentions to Allah.'
The Roman commander cried out as he urged his horse closer to Khalid and stood next to him, Please, Khalid, teach me Islam!' He submitted himself to Islam and prayed two rak'ahs. Soon, combat erupted and once again, the Roman Jerjah fought, but this time on the Muslim side until he won martyrdom.