Overcoming doubt through faith

قَالَ رَبِّ أَنَّىٰ يَكُونُ لِى غُلَـٰمٌ وَقَدْ بَلَغَنِىَ ٱلْكِبَرُ وَٱمْرَأَتِى عَاقِرٌ ۖ قَالَ كَذَٰلِكَ ٱللَّهُ يَفْعَلُ مَا يَشَآءُ

He said, "My Lord, how will I have a boy when I have reached old age and my wife is barren?" He [the angel] said, "Such is Allāh; He does what He wills."

قَالَ كَذَٰلِكَ قَالَ رَبُّكَ هُوَ عَلَىَّ هَيِّنٌ وَقَدْ خَلَقْتُكَ مِن قَبْلُ وَلَمْ تَكُ شَيْـًٔا

[An angel] said, "Thus [it will be]; your Lord says, 'It is easy for Me, for I created you before, while you were nothing.'"