Your book reads, “Muhammad is the Messenger of Allah and those with him are forceful against the disbelievers, merciful among themselves.” (48:29) Jesus says love your enemies. I feel like Christianity is a religion of peace and Muslims are only good to people who follow their religion.
In the name of Allah, the Beneficent, the Merciful
The verse you have cited refers specifically to the aggressive unbelievers who use violence in order to prevent people from practicing Islam. The verse reads:
مُّحَمَّدٌ رَّسُولُ اللَّهِ وَالَّذِينَ مَعَهُ أَشِدَّاءُ عَلَى الْكُفَّارِ رُحَمَاءُ بَيْنَهُمْ تَرَاهُمْ
Muhammad is the Messenger of Allah and those with him are stern against the unbelievers, merciful among themselves.
Surah Al-Fath 48:29
In the original Arabic, there is a shadda above the letter fa which indicates emphasis, meaning the word is more properly translated as “aggressive unbelievers” (kuffar) and not simply “unbelievers” (kafirin). This distinction is made clearer just a few verses earlier in the surah. Allah says:
هُمُ الَّذِينَ كَفَرُوا وَصَدُّوكُمْ عَنِ الْمَسْجِدِ الْحَرَامِ وَالْهَدْيَ مَعْكُوفًا أَن يَبْلُغَ مَحِلَّهُ
They are the ones who disbelieved and obstructed you from the Sacred Mosque while the offering was prevented from reaching its place of sacrifice.
Surah Al-Fath 48:25
This distinction is made elsewhere in the Quran. Allah says:
الَّذِينَ كَفَرُوا وَصَدُّوا عَن سَبِيلِ اللَّهِ أَضَلَّ أَعْمَالَهُمْ
Those who disbelieve and prevent people from the way of Allah – He will nullify their deeds.
Surah Muhammad 47:1
And Allah says:
لَّا يَنْهَاكُمُ اللَّهُ عَنِ الَّذِينَ لَمْ يُقَاتِلُوكُمْ فِي الدِّينِ وَلَمْ يُخْرِجُوكُم مِّن دِيَارِكُمْ أَن تَبَرُّوهُمْ وَتُقْسِطُوا إِلَيْهِمْ ۚ إِنَّ اللَّهَ يُحِبُّ الْمُقْسِطِينَ
Allah does not forbid you from being kind and just with those who do not fight you because of religion and do not expel you from your homes. Verily, Allah loves those who act justly.
Surah Al-Mumtahina 60:8
Therefore, the Muslims should be stern against those who use violence to prevent people from freely practicing Islam, not simply those who are not Muslims.
Jesus Christ, peace and blessings be upon him, was in fact very stern with some of his enemies among the corrupted scholars and men of religion. In a famous passage, Jesus rebukes the Pharisees:
But woe to you, scribes and Pharisees, hypocrites! You shut the kingdom of heaven against men; for you neither enter yourselves, nor allow those who would enter to go in…
Woe to you, scribes and Pharisees, hypocrites! For you tithe mint and dill and cummin, and have neglected the weightier matters of the law, justice and mercy and faith; these you ought to have done, without neglecting the others. You blind guides, straining out a gnat and swallowing a camel!
Woe to you, scribes and Pharisees, hypocrites! For you are like whitewashed tombs, which outwardly appear beautiful, but within they are full of dead men’s bones and all uncleanness. So you also outwardly appear righteous to men, but within you are full of hypocrisy and iniquity.
Woe to you, scribes and Pharisees, hypocrites! For you build the tombs of the prophets and adorn the monuments of the righteous…
Source: Matthew 23:13-29
Likewise, Jesus was very stern with the money-changers who were cheating people inside the very house of Allah. As it is written:
In the temple Jesus found those who were selling oxen and sheep and pigeons, and the money-changers at their business; and making a whip of cords, he drove them all, with the sheep and oxen, out of the temple; and he poured out the coins of the money-changers and overturned their tables.
Source: John 2:14-15
So, Jesus did love good for his enemies but he was wise enough to know when to be harsh with the most sinful of the unbelievers. Just as a deeply rusted coin cannot be scrubbed clean with a gentle scrub, so also are hearts deeply rusted with sin not made pure with gentle preaching. We could call this “tough love.” Jesus was kind and merciful to the common people, even a prostitute, but he strongly admonished the men of religion who should have known better.
In the same way, the Prophet Muhammad taught the Muslims to love good for their enemies.
Anas ibn Malik reported: The Prophet, peace and blessings be upon him, said:
لَا يُؤْمِنُ أَحَدُكُمْ حَتَّى يُحِبَّ لِلنَّاسِ مَا يُحِبُّ لِنَفْسِهِ وَحَتَّى يُحِبَّ الْمَرْءَ لَا يُحِبُّهُ إِلَّا لِلَّهِ عَزَّ وَجَلَّ
None of you has faith until he loves for the people what he loves for himself; and until he loves a person only for the sake of Allah the Exalted.
Source: Musnad Ahmad 13463, Grade: Sahih
We can point to many examples in the Prophet’s life – too many to cite in this one article – in which he was kind and merciful to even his most violent enemies. The most famous of these examples is when the city of Mecca surrendered to the Prophet without a fight. After twenty-three years of persecution, the Prophet finally had power over his enemies. His response was to forgive them.
Al-Qasim ibn Salim reported: When they came to the Ka’bah they were holding onto its door and the Prophet, peace and blessings be upon him, said:
مَا تَقُولُونَ وَمَا تَظُنُّونَ
What do you say? What do you think?
They said three times, “We say you are the son of our brother.” The Prophet said:
أَقُولُ كَمَا قَالَ يُوسُفُ لَا تَثْرِيبَ عَلَيْكُمُ الْيَوْمَ يَغْفِرُ اللَّهُ لَكُمْ وَهُوَ أَرْحَمُ الرَّاحِمِينَ
I say to you as Joseph said to his brothers: No blame upon you today. Allah will forgive you, and He is the most merciful of the merciful. (12:92)
Abu Yusuf reported: When they had gathered in front of the sacred mosque, the Prophet, peace and blessings be upon him, said:
مَا تَرَوْنَ أَنِّي صَانِعٌ بِكُمْ
What do you think I will do with you?
They said, “Only good, O noble brother, son of a noble brother.” The Prophet said:
اذْهَبُوا فَأَنْتُمُ الطُّلَقَاءُ
Go, you are free.
Source: Sunan Al-Kubra Al-Bayhaqi 17714, Grade: Sahih
It was the Prophet’s message to be merciful to all of creation, friends and enemies alike.
Abdullah ibn Amr reported: The Messenger of Allah, peace and blessings be upon him, said:
الرَّاحِمُونَ يَرْحَمُهُمْ الرَّحْمَنُ ارْحَمُوا أَهْلَ الْأَرْضِ يَرْحَمْكُمْ مَنْ فِي السَّمَاءِ
Those who are merciful will be shown mercy by the Merciful; be merciful to the people of the earth and the One above the heavens will have mercy upon you.
Source: Sunan Abu Dawud 4941, Grade: Sahih
Likewise, the Prophet taught his companions to be kind to their neighbors no matter what religion they followed.
Mujahid reported: I was with Abdullah ibn Amr while his servant was skinning a sheep. He said, “O boy, when you finish up, then start with the Jewish neighbor.” A man there exclaimed, “Jewish? May Allah correct you!” He replied:
إِنِّي سَمِعْتُ النَّبِيَّ صلى الله عليه وسلم يُوصِي بِالْجَارِ حَتَّى خَشِينَا أَوْ رُئِينَا أَنَّهُ سَيُوَرِّثُهُ
I heard the Messenger of Allah recommending that we treat our neighbors well until we thought that he would order us to make them our heirs.
Source: Al-Adab Al-Mufrad 128, Grade: Hasan
In conclusion, the verse you have cited about being stern against unbelievers refers to only the most sinful and violent unbelievers. Furthermore, there is no contradiction on this point between the verses of the Quran and the teachings of Jesus, upon him be peace, as recorded in the New Testament.
Success comes from Allah, and Allah knows best.