When he called to his Lord a private supplication.
Tafseer
{ إذ } متعلق برحمة { نادى ربه نداءً } مشتملاً على دعاء { خفيا } سرا جوف الليل لأنه أسرع للإجابة .
{When} is related to mercy. {He called upon his Lord with a call} including a supplication {secretly} in the depths of the night because He is quicker to respond.
