سُبْحَانَ ٱللَّٰهِ
Holy Qur'an
Al-Qur'an
Kids Qur'an
This, I believe, is the meaning of the expression al-musallin (lit., "the praying ones"), which evidently does not relate here to the mere ritual of prayer but, rather, as the next verse shows, to the attitude of mind and the spiritual need underlying it. In this sense it connects with the statement in verse {19} that "man is born with a restless disposition" which, when rightly used, leads him towards conscious spiritual growth, as well as to freedom from all self-pity and selfishness.
The description of those devoted to Prayer is given in a number of clauses that follow, introduced by the words "Those who..." "Devoted to Prayer" is here but another aspect of what is described elsewhere as the Faithful and the Righteous. Devotion to prayer does not mean merely a certain number of formal rites or prostrations. It means a complete surrender of one's being to Allah. This means an earnest approach to and realisation of Allah's Presence ("steadfastness in Prayer"); acts of practical and real charity; and attempt to read this life in terms of the Hereafter; the seeking of the Peace of Allah and avoidance of His displeasure; chastity; probity true and firm witness; and guarding the prayer. (verse 34).