The blessed Verse 29 is saying that upon hearing such glad tiding...

The blessed Verse 29 is saying that upon hearing such glad tiding, Sarah, Abraham’s (as) wife, hastened toward the room with a loud voice (fi sarratin) saying: “How may I conceive a child when I am an old [barren] woman.” Qur’anic exegets maintain that Sarah and Abraham (as) were ninety five and one hundred and ninety years of age respectively at the time. The blessed Verse 30 is saying that replying to Abraham’s (as) wife seized by great surprise and fear, the angles said: “Thus says your Lord.

Indeed, He is the All-Wise, the Omniscient,” i.e. he is All-Aware of all good and evil things. The angels might have intended to say that they were on a mission from God Almighty to bear them glad tidings rather than saying something of their own, aiming to make her understand that God Almighty willed to reflect his Omnipotence to the world that whatever He willed would be realized and there was nothing impossible against His Omnipotence.

Thus, the angels said: “He is the All-Wise, the Omniscient.” The emphatic conjunction inna (“behold, verily, truly”) indicates that whatever God Almighty wills is based upon His Wisdom and Omniscience as to improving the affairs and vanity may never penetrate his Sacred Divine Presence.

[Stones] marked by your Lord for [the perdition of] transgressors of Divine Bounds. The Arabic word khatb designates ‘significant affair or concern’ and musawwama denotes ‘marked.’ Lot (as) was a relative of Abraham (as) who propagated monotheism in the region of Sodom, Jordan, at the time. Lot’s (as) people were promiscuous and also sodomizers inattentive to Prophet Lot’s (as) warnings.

As a consequence, God Almighty caused the destruction of their region and their story is mentioned in Chapters 7, 11, 15, and 29. The blessed Verse 31 is saying that when Prophet Abraham (as) recognized the angels through the light of his heart and learned that they were on a significant mission, he inquired about their purpose.