“ Woe to the praying ones, who are unmindful of their prayers; Those who (want but) to be seen (of man).” (Surat al-Maun, 107:4-6)
What gives our prayers rectitude is our consciousness that we are prostrating ourselves before Allah only in order to express our devotion to Him. That is why Allah commands believers to “stand before Allah in a devout (frame of mind)” (Surat al-Baqara, 2:238)Another verse describes the believers as "those who offer their prayers with all solemnity and submissiveness.” (Surat al-Mumenoon, 23:2)
Solemnity in this verse means experiencing fear accompanied by deep respect and having one’s heart filled with awe. Such a prayer increases one's faith and closeness to Allah. It keeps man standing firm.
“Recite the what is sent of the Book by inspiration to you, and establish regular prayer: for prayer restrains from shameful and unjust deeds; and remembrance of Allah is the greatest (thing in life) without doubt. And Allah knows the (deeds) that you do.” (Surat al-Ankaboot, 29:45)