Muhammad said: Authority (sultan) is only termed 'sultan' because it is the proof of Allah, may He be glorified and exalted, in His land.
قَالَ محمدٌ: وَالسُّلْطَانُ إِنَّمَا سُمِّيَ سُلْطَانًا؛ لأَنَّهُ حُجَّةُ اللَّهِ ﷿ فِي أرضه.