Once in the middle of the night Allah's Messenger (ﷺ) (p.b.u.h) went out and prayed in the mosque and somemen prayed with him. The next morning the people spoke about it and so more people gathered andprayed with him (in the second night). They circulated the news in the morning, and so, on the thirdnight the number of people increased greatly. Allah's Messenger (ﷺ) (p.b.u.h) came out and they prayedbehind him. On the fourth night the mosque was overwhelmed by the people till it could notaccommodate them. Allah's Messenger (ﷺ) came out only for the Fajr prayer and when he finished theprayer, he faced the people and recited "Tashah-hud" (I testify that none has the right to beworshipped but Allah and that Muhammad is His Apostle), and then said, "Amma ba'du. Verily yourpresence (in the mosque at night) was not hidden from me, but I was afraid that this prayer (Prayer ofTahajjud) might be made compulsory and you might not be able to carry it out."