Question :
Is it permissible for an Imam (one leading prayer) to reserve places in the first row for a certain number of prayer performers {e.g. three} who memorize the Quran by heart ?
The Answer :
they would even draw lots to secure these privileges. And were they to realize the reward of performing Salat early, they would race for it; and were they to know the merits of Salat after nightfall (`Isha') and the dawn (Fajr) Salat, they would come to them even if they had to crawl.''{Muslim}. However, allowing someone else to take his place in the first row is disliked because there is no room for altruism when it comes to offering acts of obedience to Almighty Allah.
It is recommended that the pious who memorize the Book of Allah to stand behind the Imam, so as to help him in recitation, remind him when he forgets and replace him during the prayer if something happens to him {like if his ablution is invalidated during the prayer}. Our Prophet{PBUH} said: “Let those of you who are mature and prudent be nearer to me, and then those who are next to them.”{Muslim}.
Al-Imam An-Nawawi {May Allah have mercy on him} said: “ This Hadith stresses that men known for wisdom, knowledge and piety should stand in the first row and these should be followed by those who come next to them in these virtues. It also stresses the importance of setting the rows straight, maintaining the status of the prayer and setting an example to those behind them. “{ Sharh An-Nawawi Ala Muslim}(4/155).
It isn`t allowed for an Imam to reserve a certain place and ban prayer performers from praying in it. However, it is recommended that he asks for their permission before dedicating a certain place behind him for some of those who memorize the Quran. And Allah knows best.