Verse 41

قَالَ رَبِّ ٱجْعَل لِّىٓ ءَايَةً قَالَ ءَايَتُكَ أَلَّا تُكَلِّمَ ٱلنَّاسَ ثَلَـٰثَةَ أَيَّامٍ إِلَّا رَمْزًا وَٱذْكُر رَّبَّكَ كَثِيرًا وَسَبِّحْ بِٱلْعَشِىِّ وَٱلْإِبْكَـٰرِ

He said, Lord, give me a sign. He said your sign is that you will not speak to people for three days, except by sign language. Furthermore, commemorate your Lord constantly and glorify night and day.