Tafseer Ibn Kathir of ASH SHAFF [4]

إِنَّ اللَّهَ يُحِبُّ الَّذِينَ يُقَاتِلُونَ فِي سَبِيلِهِ صَفًّا كَأَنَّهُم بُنيَانٌ مَّرْصُوصٌ

Indeed, Allah loves those who fight in His cause in a row as though they are a [single] structure joined firmly.