In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

Ana’s Bin Maalik [radiyallaahu anhu] reported that the Prophet [sallal laahu alayhi wasallam] said – during his illness [i.e. the illness through which he passed away], “Your Arhaam! Your Arhaam!”. [i.e. relatives of the womb]

Shaikh Zayd Bin Haadi [rahimahullaah] said:

This hadeeth contains a precious advice [or command] from the noble Prophet [sallal laahu alayhi wasallam] whose Lord described him in His statement: [لَقَدۡ جَآءَڪُمۡ رَسُولٌ۬ مِّنۡ أَنفُسِڪُمۡ عَزِيزٌ عَلَيۡهِ مَا عَنِتُّمۡ حَرِيصٌ عَلَيۡڪُم بِٱلۡمُؤۡمِنِينَ رَءُوفٌ۬ رَّحِيمٌ۬ – Verily, there has come unto you a Messenger (Muhammad) from amongst yourselves (i.e. whom you know well). It grieves him that you should receive any injury or difficulty. He (Muhammad) is anxious over you (to be rightly guided, to repent to Allah, and beg Him to pardon and forgive your sins, in order that you may enter Paradise and be saved from the punishment of the Hell-fire), for the believers (he is) full of pity, kind, and merciful]. [Surah At-tawbah. Aayah 128]

It is an advice [or a command] about maintaining the ties of kinship, and indeed the command regarding it has been stated in the noble Qur’aan and in the [authentic] Prophetic Sunnah. As for in the Qur’aan, then indeed Allaah [The Blessed and Exalted] said:

يَـٰٓأَيُّہَا ٱلنَّاسُ ٱتَّقُواْ رَبَّكُمُ ٱلَّذِى خَلَقَكُم مِّن نَّفۡسٍ۬ وَٲحِدَةٍ۬ وَخَلَقَ مِنۡہَا زَوۡجَهَا وَبَثَّ مِنۡہُمَا رِجَالاً۬ كَثِيرً۬ا وَنِسَآءً۬‌ۚ وَٱتَّقُواْ ٱللَّهَ ٱلَّذِى تَسَآءَلُونَ بِهِۦ وَٱلۡأَرۡحَامَ‌ۚ إِنَّ ٱللَّهَ كَانَ عَلَيۡكُمۡ رَقِيبً۬ا

O mankind! Be dutiful to your Lord, Who created you from a single person (Adam), and from him (Adam) He created his wife [Hawwa (Eve)], and from them both He created many men and women and fear Allah through Whom you demand your mutual (rights), and (do not cut the relations of) the wombs (kinship) . Surely, Allah is Ever an All-Watcher over you. [Surah An-Nisaa. Aayah 1]

The Prophet [sallal laahu alayhi wasallam] advised [or commanded one] to maintain the ties of kinship and promised reward – in this life and the next – for it. These are upright exhortations [or commands].

The intent behind the word Ar-Rahim – [relation of the womb] – are one’s relatives on the father’s and mother’s side, and they are of different levels [or categories]. Maintaining ties with them aids a person in his worldly affairs to fulfil his needs and makes his affairs easy by the permission of Allaah. And with regards to [deeds related to the] afterlife, it is one of the best deeds through which a servant seeks to get close to Allaah [i.e. to receive the love of Allaah and reward, and repel punishment].

An Excerpt from At-taleeqaat al-maleehah Alaa silsilah al-ahaadeeth As-Saheehah vol 1. Page 62. Slightly paraphrased.