قَالُوا لَا تَوْجَلْ إِنَّا نُبَشِّرُكَ بِغُلَامٍ عَلِيمٍ ﴿۵۳﴾ قَالَ أَبَشَّرْتُمُونِي عَلَى أَنْ مَسَّنِيَ الْكِبَرُ فَبِمَ تُبَشِّرُونَ ﴿۵۴﴾ قَالُوا بَشَّرْنَاكَ بِالْحَقِّ فَلَا تَكُنْ مِنَ الْقَانِطِينَ ﴿۵۵﴾ قَالَ وَمَنْ يَقْنَطُ مِنْ رَحْمَةِ رَبِّهِ إِلَّا الضَّالُّونَ ﴿۵۶﴾

﴾53﴿ Qaaloo la tawjal innaa nubashshiruka bighulaamin 'aleem
﴾54﴿ Qaala abashshartumoonee 'alaaa am massaniyal kibaru fabima tubashshiroon
﴾55﴿ Qaaloo bashsharnaaka bilhaqqi falaa takum minal qaaniteen
﴾56﴿ Qaala wa mai yaqnatu mir rahmati Rabbiheee illad daaaloon

﴾53﴿ They said, 'Do not be afraid. Indeed, we give you glad tidings of a knowledgeable son
﴾54﴿ He said, Do you give me glad tidings despite my old age, So what is this glad tidings you give me
﴾55﴿ They said, We have given you glad tidings in truth, so do not be of the despairing
﴾56﴿ And he said, None despairs of the mercy of their Lord except those who are astray

[53] What is meant by (بِغُلَامٍ) is Ishaq (Isaac), peace be upon him, and what is meant by (عَلِيمٍ) is prophethood.
[54] This amazement of Ibrahim (peace be upon him) was based on the general human custom—not out of denial of Allah’s power.
(فَبِمَ تُبَشِّرُونَ) – This is a real question, meaning: In what way is this glad tidings being given?—Is old age going to be removed, or will the glad tidings come despite remaining in this state of old age?
[55] What is meant by “حق” (the truth) is something absolutely true, in which there is no doubt whatsoever.
And since amazement, outwardly, may indicate despair, the angels therefore said: (فَلَا تَكُنْ مِنَ الْقَانِطِينَ) – So do not be among those who despair.
[56] That is, the amazement of Ibrahim (peace be upon him) was not due to despair, but rather because of the apparent worldly causes.
Despair from the mercy of Allah the Exalted leads to misguidance, because the one who despairs of Allah’s mercy is ignorant and denies His power. This is mentioned in verse 87 of Surah Yusuf.
Note: In Surah Yusuf, kufr (disbelief) is mentioned alongside ya’s (despair), and in this Surah, ḍalāl (misguidance) is mentioned alongside qunūṭ (despondency). The wisdom in this is that ya’s refers to inner despair of the heart, and kufr is also an act of the heart. While qunūṭ refers to the kind of despair whose effects visibly appear on the face—and ḍalāl is used for outward misguidance. Thus, the wording in both cases is perfectly appropriate and interconnected.