The World Federation One Stop Fiqh

Ruling 936

If a person wants to join ‘allāhu akbar’ with something after it, for example, with ‘bismil lāhir raḥmānir raḥīm’, it is better that the letter ‘r’ in ‘akbar’ be given a ḍammah [i.e. it would be pronounced ‘akbaru’]. However, the recommended precaution is that one should not join it in obligatory prayers.