Condemned are the makers of the ditch, the fire 'pit' filled with fuel when they sat around it, watching what they had 'ordered to be' done to the believers, who they resented for no reason other than belief in God—the Almighty, the Praiseworthy, 'the one' to Whom belongs the kingdom of the heavens and earth. And God is a Witness over all things. Those who persecute the believing men and women and then do not repent will certainly suffer the punishment of Hell and the torment of burning.
In the context of these verses, there is a detail in Sahih Muslim (7511). Companion Suhaib reported that once Prophet Muhammad told him that a boy once worked for the king (Dhu Nuwas) as a magician. The boy was still learning and he daily visited the experienced magician. Every day, the boy met a monk on his way to the other magician. The monk taught the boy about faith in God, God's Mercy and God's rewards in the afterlife. Upon listening to the monk's talk daily, the boy accepted Christianity and restored his faith in God. The young boy started to convey the truth to the people of the city. As he learned the magic, he started to cure the sick with the permission of God. The king on hearing this, demanded the boy be killed. However, God saved the young boy whenever they planned to kill him. The boy told the king that if he wants to kill me, he has to gather all the people of the city and shoot an arrow while saying 'In the name of God, the Lord of this young boy'. The king accepted the boy's demand and did the same. On seeing that the young boy was killed in the name of God, the people of the city realised that the boy was on the true path. All the people that were standing there, accepted Christianity. The king was furious. The king ordered his men to dig big ditches and fill them with fire. Then the king ordered the believers to return to their original religion or else they will be thrown into the fire. The believers refused to leave their religion and all of them were thrown into the fire. A mother, thinking of her child, was reluctant to go into the fire. It happened so, that her child spoke and told her that 'Mother, this is the truth'.