Al-Qasim bin Abdul-Rahman (may Allah have mercy on him) said: Al-Walid bin Uqbah delayed the prayer, so Sayyiduna Ibn Mas'ud (may Allah be pleased with him) ordered the mu'adhdhin, and he called the iqamah (again); then he himself stepped forward and led the people in prayer. At that, al-Walid sent a message to him: What is this you have done? Has some new order come to you from the Commander of the Believers, or have you introduced something new (on your own)? Sayyiduna Ibn Mas'ud (may Allah be pleased with him) said: "None of that happened. Neither Allah nor His Messenger (peace and blessings be upon him) has commanded us to wait for you with our prayer while you are busy with your own affairs."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9467