Al Salamu 'Alaykum.
Hadrat Mawlana Rasheed Ahmad Gangohi (rahmatullahi alaih) had once gone for the dastaarbandi jalsah in Deoband. On account of the large crowd and the multitudes of people greeting Hadrat, there was a slight delay in Hadhrat coming to the musjid. When Moulana had reached the musjid, the qiraat had already commenced. After the salaah was over it was noticed that Mawlana was overcome by extreme grief and remorse. With intense anguish he said: “How sad it is, that today I have missed my takbeer-e-ula after twenty-two years.”(Tazkirat-ur-Rasheed, vol. 2, p. 16)
Mawlana Zafar Ahmad Uthmani (rahmatullahi alaih) relates: “I remained for six years in the khidmat of Hadrat Mawlana Khaleel Ahmad Saharanpuri (rahmatullahi alaih). Never did I witness Hadrat missing his takbeer-e-ula. However, there was one occasion when Hadhrat’s mouth began to bleed continuously whilst making wudhu for Fajr salaah. Hadrat then sent a message with one of his attendants to the musjid that the jamaat should not be delayed on account of him. This was the only time that I had witnessed Hadrat missing the takbeer-e-ula, though he managed to get the first rakat.” (Tazkirat-ul-Khaleel, p. 345)Taken from : http://alhaadi.org.za/articles/lessons-from-the-lives-of-the-pious/1465-importance-of-takbeer-e-ula-in-the-lives-of-our-akaabir-part-2.html