[1]

Here, “specified days” refers to the duration from the Fajr of 9^th Dhu’l Hijjah until the ꜤAṣr of 13^th Dhū Al-Ḥijjah (the Days of Tashrīq). The remembrance of Allah Almighty means proclaiming Allah’s greatness (takbīr) after the prescribed prayers and during the stoning of the pillars. The verse is interpreted as an instruction to remember Allah Almighty during the stay at Minā.

[2]

This means two days after the 10^th of Dhū Al-Ḥijjah, i.e., when he has completed the stoning for the 12^th.  If one returns from Minā after the stoning on the 12^th, there is no sin upon him even though it is better to return after the stoning of the pillars on the 13^th.