Why did Allah ordain the hijab for women during prayer, despite His saying: "And He is with you wherever you are," and knowing that He sees them whether they wear it or not?

Concealing the 'awrah (intimate parts) is a condition for the validity of prayer, mandated by Allah upon His servants, men and women alike, so that they may stand before Him in the most complete of appearances. Allah has commanded the taking of adornment for prayer, saying: "O Children of Adam, take your adornment at every place of prayer." Indeed, Allah is most deserving of adornment and modesty. Al-Khateeb Al-Shirbini states that concealing the 'awrah is a condition for the validity of prayer, citing the aforementioned verse and the hadith: "Allah does not accept the prayer of a menstruating woman except with a head covering" (meaning a mature woman). The wisdom behind concealment in prayer is adornment and purification for one who stands before the King of Kings. A Muslim obeys Allah's rulings out of submission and compliance, knowing that Allah does not legislate anything except for wisdom and benefit.