Is it permissible to recall the delights of Paradise during prayer if doing so leads to devotion (khushu') and sincerity (ikhlas) in it?

Remembering the delights of Paradise during prayer is permissible, especially if it aids in achieving khushu' (devotional humility) and sincerity. This is a form of contemplation on matters of the Hereafter, which helps in attaining khushu'. Allah has commanded the establishment of prayer, and its establishment is both outwardly and inwardly. Khushu' is the essence and spirit of prayer, and a person only gains from their prayer what they comprehend of it.