Is there any Islamic equivalent of Khumra (with examples)

Question

Judaism has a concept called Khumra, which puts additional obligation and prohibitions around Torah. Is there any equivalent in Islam, and if yes, what are some examples

Answer 1

Based on my understanding or interpretation of the linked Wikipedia article I'd say:
Beside applying a none ordered or better optional act (sunnah) regularly, based on ones own will there's also the concept of "nadhr" النذر (English wikipedia here refers to Religious vows), which is quoted in the Qur'an in several verses: As a statement of Mariam the mother of 'Isa (Jesus):

... 'Indeed, I have vowed to the Most Merciful abstention, so I will not speak today to [any] man.' " (19:26)

It is also quoted as an attribute of righteous people:

Indeed, the righteous will drink from a cup [of wine] whose mixture is of Kafur,(5)
A spring of which the [righteous] servants of Allah will drink; they will make it gush forth in force [and abundance].(6)
They [are those who] fulfill [their] vows and fear a Day whose evil will be widespread.].(7) (76:5-7)

It's also quoted as good deed after hajj (pilgrimage)

Then let them end their untidiness and fulfill their vows and perform Tawaf around the ancient House." (22:29 also read the verses before for more context)

From the above examples we see that Islam affirmed this concept to some extent for details read the following fatwa islamqa #2587. The Arabic wikipedia page offers some more evidences from the Quran such as (2:245 here defined as goodly loan, 2:270, 3:45) and of course there are many prophetic traditions (ahadith plural of hadith) on this matter:

• Do not take vows, for a vow has no effect against Fate; it is only from the miserly that something is extracted. (Sahih Muslim and others)

• "In fact, vowing does not prevent anything, but it makes a miser to spend his property." (Sahih al-Bukhari, Sahih Muslim and others)
• "Whoever vows to obey Allah, let him obey Him. Whoever vows to disobey Allah, let him not disobey Him." (Al-Muwatta', Sahih al-Bukhari -different versions with a slightly different wording- and others)
• "...There is no fulfillment of the vow in an act of disobedience, nor in an act over which a person has no control. ..." (From a long ahdith in sahih Muslim also compiled by abu Dawod in his sunan)

These give us some rulings about vows: Shortly one should fulfill vows unless its for an act of disobedience or an act one doesn't have control over!
It also seems that vows are not recommended as they are obligations that may take you beyond your capacity!

Here some examples of what I was pointing at in my first sentence:

For example it is sunnah (just a good deed in which we follow the example of our Prophet Muhammad) to fast Mondays and Thursdays, or the 3 days in the middle of a lunar month. Some people do their best to do such acts regularly (as Muhammad was doing it), each week, each month respectively. This may basically be connected to a vow!

It is a known story that the founder of University of Al Quaraouiyine (the oldest university on earth) in Fes was a woman called Fatima al-Firhia whom had vowed to fast until the achievement of this building!
Other examples could be to make a vow to do some kind of worship or charity if one may achieve to perform hajj (as a person who's actually not able to do so) or if one recovers from a long illness etc..