Jilbab is not a piece of cloth on your head

I see many sisters entering the Masjid from the men’s entrance, or standing idle in the hallways or where there is a chance of unnecessary mixing with the brothers. What for?
Don’t we have a separate entrance for ourselves? Why do you think Allaah ordained the Hijaab in the first place? To avoid fitnah, by reducing temptation and separating the genders.

“The Prophet (Sal Allaahu Alaiyhi wa Sallam) said to the women on his way out of the mosque when he saw men and women mixing together on their way home: ‘Give way (i.e., walk to the sides) as it is not appropriate for you to walk in the middle the road.’ Thereafter, women would walk so close to the wall that their dresses would get caught on it.” (Abu Dawood)

Hijaab is also to conceal your sister

Although some sisters wear the Hijaab themselves, they forget that they cannot talk about another sister and her beauty in front of their own husbands, brothers, etc. Remember, part of your Hijaab is to cover your sisters ‘awrah’ as well.
The Prophet (Sal Allaahu Alaiyhi wa Sallam) said: “No woman should mix with a woman and describe her to her husband so that it is as if he can see her.” (Muslim)

May Allah guide us and bless us with the TRUE understanding of His Deen. Ameen.