What aspect of the preaching work is illustrated by the fact that the leaven ferments the whole mass?
وَلكِنْ رَغْمَ أَنَّنَا قَدْ لَا نُلَاحِظُ ٱلنُّمُوَّ فِي ٱلْبِدَايَةِ ،‏ تَصِيرُ نَتَائِجُهُ فِي ٱلنِّهَايَةِ ظَاهِرَةً لِلْعِيَانِ .‏