Its Legal Status
     There is disagreement among scholars concerning the legal    status of Sa'i between Safa and Marwah. These scholars    may be divided into three groups:           'Aishah, and from among the Companions Ibn 'Umar,     and Jabir hold that Sa'i of Safa and Marwah is an     essential part of Hajj rites. Malik, AshShafi'i,     and Ahmad (according to one narration from him)     also hold a similar opinion. Thus if a pilgrim     fails to perform Sa 'i his Hajj will be void and     his offering of a sacrifice will not be enough to     make up for it. These scholars based their     opinion on the following:           a) Az-Zuhari reported from 'Urwah that he said: "I asked    'Aishah about it and recited to her the verse "Behold !    Safa and Marwah are among the symbols of Allah. So if    those who visit the House in the season or at other    times, compass round them, there is no sin in them."
    (Qur'an 2.158) Then I said to her, "By Allah, I see that    (in light of this verse) there is no sin on a person who    does not perform Sa'i between them!" 'Aishah said to me,    "O my nephew! That is the worst interpretation you have    put on this verse. It does not mean what you say. If it    had meant what you say it means, then the wording should    have been 'should not compass them round.' This verse was    revealed concerning the Ansar, who used to worship the    idol Manat in an area called Al-Mushallal. They feared    they were committing a sin by walking between Safa and    Marwah.|"After they embraced Islam they asked the Prophet    (peace be upon him) about it. At this Allah revealed this    verse. The Prophet (peace be upon him) has by his    practice affirmed authenticity of the Sa'i between these    two hills, and no one has the authority to abandon it.
    (Bukhari)           These scholars, in support of their standpoint,     refer to the Qur' anic verse 2:158, which states     there is no sin if a person neglects it. In other     words it is not obligatory. That it is only     sunnah is also obvious from the fact that Safa     and Marwah are described as "the symbols of     Allah."
           It is reported that the Mushaf of Ubaiy and Ibn Mas'ud    read " ..if those who visit the House in the season or at    other times, should not compass them, it is no sin in    them." This is not the Qur'anic text, but it does convey    an important piece of information and an interpretation    of the Qur'anic text.
         The author of Al-Mughni prefers this opinion, and says:           This is preferable, because the argument of those     holding it to be wajib supports the absoluteness     of the obligation rather than the principle that     anything needed to fulfill an obligation (wajib)     is also obligatory (wajib).
           'Aishah's statement in this respect is different     from what other Companions of the Prophet (peace     be upon him) have narrated.
           The hadith of the daughter of Abi Tajrah has     among its narrators one called Abdullah bin     Al-Mu'mal, who is controversial. According to him     it is obligatory, whereas it is only wajib.
           The verse quoted above was revealed concerning     those people who feared they would be committing     a sin if they walked between Safa and Marwah as     they used to do in the days of Jahiliyya while     two idols were set on top of Safa and Marwah.
      
We are identifying and building the related set of Ayahs for this Hadith. Please share your feedback and let us know if you identify any referencing issues.
"When a person dies, his works end, except for three: ongoing charity, knowledge that is benefited from, and a righteous child who prays for him."
Prophet Mohammed (PBUH)
"The best of what a man leaves behind are three: a righteous child who supplicates for him, ongoing charity the reward of which reaches him, and knowledge that is acted upon after him."
Sunan Ibn Mājah
"Every day two angels come down from Heaven and one of them says, 'O Allah! Compensate every person who spends in Your Cause,' and the other (angel) says, 'O Allah! Destroy every miser.'"
Sahih Bukhari