Tell the believing men to lower their gaze and be modest. That is purer for them. Lo! Allah is aware of what they do.And tell the believing women to lower their gaze and be modest, and not to expose their adornment except that which is apparent, and to draw their veils over their bosoms, and not to reveal their adornment except to their own husbands or fathers or husbands’ fathers, or their sons or their husbands’ sons, or their brothers or their brothers’ sons or sisters’ sons, or their women, or their slaves, or male attendants who lack vigour, or children who know nothing of women’s nakedness. And let them not stamp their feet so as to reveal what they hide of their adornment. And turn to Allah together, O believers, in order that you may succeed.
The Quran 24:30-31 (Surah an-Nur)
Islam asks men and women to practise modesty, both in dress and behavior. Hijab in Islam has been a topic of hot debate and discussion for quite a while now.
Why Does Islam Make Hijab Mandatory?
This is a common and oft-asked question.
Hijab is symbolic of decency and modesty. In Surah al-Ahzab, Allah gives a very good reason: 
O Prophet! Tell your wives and your daughters and the women of the believers to draw their cloaks close around them (when they go abroad). That will be better, so that they may be recognized and not annoyed.
Thus, the Quran asks women to wear Hijab so that they can be recognized as believing women. As such, it can prevent mishaps in scenarios where harassment is a possibility. The purpose, therefore, is not to curtail liberty but to ensure safety.
Is the Face Veil Mandatory in Islam?
Th above verses show that Hijab in itself is mandatory. However, what about the face veil?
There are two schools of thought. The first one believes that the Hijab must cover the hands and face, while the other school of thought states that the Hijab should only cover the body, that is, face and hands are not necessary.
Arguments Stating That Face Veil is Not Mandatory
Narrated Hz Aisha (RA): 
Asma, daughter of Abu Bakr (RA), entered upon the Messenger of Allah (PBUH) wearing thin clothes. The Messenger of Allah (PBUH) turned his attention from her. He said: “O Asma! When a woman reaches puberty, it does not suit her that she displays her parts of body except this and this, and he pointed to his face and hands.”
Narrated Hz Abdullah bin Abbas (RA): 
During the day of Nahr (10th Dhu al-Hijjah), when Al-Fadl bin Abbas (RA) was riding behind the Prophet (PBUH) on his she -camel, a beautiful woman from the tribe of Khath’am came, asking the verdict of Allah’s Messenger. Al-Fadl (RA) started looking at her as her beauty attracted him. The Prophet looked behind while Al-Fadl (RA) was looking at her; so the Prophet held out his hand backwards and caught the chin of Al-Fadl (RA) and turned his face (to the other side) in order that he should not gaze at her….”
In this Hadith, we learn that Al-Fadl (RA) was looking at the lady because of her beauty. In spite of this, the Prophet (PBUH) did not instruct the lady to cover her face, but instead turned the face of Al-Fadl (RA) in the other direction, in order to prevent him from staring at her.
The above narratives are used in support of the argument that face veil is not mandatory.
Arguments Stating That Face Veil is Mandatory
Narrated Hz Aisha (RA): 
Allah’s Messenger (PBUH) used to offer the Fajr prayer and some believing women covered with their veiling sheets used to attend the Fajr prayer with him and then they would return to their homes unrecognized .
Obviously, if a woman returned home unrecognized, it means she must have covered her face.
Narrated Safiyah bint Shaiba (RA): 
Hz Aisha (RA) used to say: When (the Verse): “They should draw their veils over their bosoms,” was revealed, (the ladies) cut their waist sheets at the edges and covered their heads and faces with those cut pieces of cloth.
Thus, scholars in support of face veil consider it to be a mandatory adornment.
Rather than siding in favor of or against the face veil, let us focus on the “Hijab” part for now, and view it as an act of worship.
Obedience to the Command of Allah is a form of worship, even if it is in matters of dress. Thus, to dress as Allah has commanded is a way of serving or worshiping Him. Naturally, why should one abandon an act that comes under worship and can fetch you reward on the Day of Judgement?
In a nutshell, Hijab is not a constraint for Muslim women, but an ornament for them. In fact, if I were to add, it is something that ensures piety and modesty in this world and great rewards in the Hereafter.
- The Quran 33:59 (Surah al-Ahzab)
- Sunan Abi Dawud Book 34 Hadith 4092
- Sahih Bukhari Vol 8 Book 74 Hadith 247
- Sahih Bukhari Vol 1 Book 8 Hadith 368
- Sahih Bukhari Vol 6 Book 60 Hadith 282
photo by The Clear Communication People