What is the wisdom behind the servants of the people of Paradise being immortalized youths, young in age? Is the reason for this to avoid sexual arousal that might be caused by the presence of adult men or women who are not permissible for marriage?

The revelation informed us that the servants of the people of Paradise are immortal youths (wildan mukhalladun), as stated in His Almighty's saying: "There will circulate among them immortal youths" (Quran 56:17), and "And there will circulate among them young boys (ghilman) [serving them] as if they were pearls well-protected" (Quran 52:24). Here, "ghilman" refers to "wildan." So, "immortal" means their perpetual youth without change.

The wisdom behind them being youths might be the suitability of their age for entering upon and serving a man's wives, as the entry of an adult would contradict the description of "houris restricted in pavilions."

It may also indicate that service requires constant speed and movement, as they are described: "When you see them, you would think them scattered pearls" (Quran 76:19), which suits the movement and agility of a young boy.

It may also suggest that these servants do not tire of serving, just as a young child does not tire of movement.

All of this is an endeavor to discern aspects of wisdom, and Allah knows best the true extent of His wisdom.