In verse 2:234 of the Holy Quran, Allah (swt) says,
“And (as for) those of you who die and leave wives behind, they should keep themselves in waiting for four months and ten days. Then when they have fully attained their term, there is no blame on you for what they do for themselves in a lawful manner; and Allah is Aware of what you do.”
The iddat or waiting period (of four months and ten days) is obligatory for every woman after the death of the husband, irrespective of whether she is divorced or not and whether she is young or old. Only pregnant women are exempted from this rule because their waiting period/ iddat ends when they deliver a child. During this waiting period the widow is not supposed to adorn themselves with make-up and showy clothes. She should continue to live in the house where her husband passed away. However, these prohibitions are not meant for those women who have been given talaq-ar-raji or revocable divorce.
After the waiting period is over the widows can get back to their normal routines. They are permitted to adorn themselves and with the permission and consultation of their guardians, they can seek a suitable marriage proposal for them.
Addressing the guardians of the widows, the Holy Quran says in verse 2:234 that there is no sin on them if the widows desire to get married for the second time.
This verse shows that Islam encourages widow remarriage. Therefore, the practice of widow remarriage should not be looked down upon in the society and neither should it be hindered in any way.