Shaykh Bin Baaz رحمه الله، said:

“If an individual or a congregation prays without doing the iqamah, then the prayer is valid. However, the person is required to repent to Allaah for that [action].” End quote. [Majmoo’ul Fataawa (10-359)]

Translated by

AbdulFattaah Bin Uthman
Abu Fajr