هُوَ ٱلَّذِىٓ أَنزَلَ ٱلسَّكِينَةَ فِى قُلُوبِ ٱلْمُؤْمِنِينَ لِيَزْدَادُوٓا۟ إِيمَـٰنًا مَّعَ إِيمَـٰنِهِمْ ۗ وَلِلَّهِ جُنُودُ ٱلسَّمَـٰوَٰتِ وَٱلْأَرْضِ ۚ وَكَانَ ٱللَّهُ عَلِيمًا حَكِيمًا
Asad Quran Translation
It is He who from on high has bestowed inner peace upon the hearts of the believers,4
so that seeing that God's are all the forces of the heavens and the earth, and that God is all-knowing, truly wise - they might grow yet more firm in their faith,5
I.e., endowed them, although they were few and practically unarmed, with calm courage in the face of the much more powerful forces of the enemy.
Lit., "so that they might add faith to their faith, seeing that God's are . .", etc. Since the latter is obviously a parenthetic clause, I have transposed it in my rendering in order to make the meaning clear.
Malik Quran Translation
It was He who sent down tranquillity into the hearts of the believers, so that they may add more faith to their Faith. To Allah belong the forces of the heavens and the earth. Allah is All-Knowledgeable, All-Wise.
Yusuf Ali Quran Translation
It is He who sent down Tranquillity into the hearts of the Believers that they may Add Faith to their Faith; for to Allah belong the Forces of the heavens and the earth; and Allah is full of Knowledge and Wisdom; 4869 4870 4871
The results were achieved by tranquillity, calmness, and cool courage among the 1400 to 1500 unarmed men who accompanied the Prophet to Hudaibiya and who were threatened with violence by the excited Quraish leaders of Makkah.
It is a casuistical question to ask. Are there degrees in Faith? The plain meaning is that believers will see one Sign of Allah after another, and with each their Faith is confirmed. During all the long years of persecution and conflict they had Faith, but when they see their old enemies actually coming out to negotiate with them, their Faith is justified, fulfilled, and confirmed: and they turn in gratitude to Allah.
There are visible forces which you see in the physical world. Men fight with armed forces, and the Muslims had to defend themselves with arms also, and not without success.
Mustafa Khattab Quran Translation
He is the One Who sent down serenity upon the hearts of the believers so that they may increase even more in their faith. To Allah ˹alone˺ belong the forces of the heavens and the earth. And Allah is All-Knowing, All-Wise.
Piktal Quran Translation
He it is Who sent down peace of reassurance into the hearts of the believers that they might add faith unto their faith. Allah's are the hosts of the heavens and the earth, and Allah is ever Knower, Wise--
Huwa allathee anzala alssakeenata fee quloobi almumineena liyazdadoo eemanan maAAa eemanihim walillahi junoodu alssamawati waalardi wakana Allahu AAaleeman hakeeman