السَّاعِي عَلَى الْأَرْمَلَةِ وَالْمِسْكِينِ كَالْمُجَاهِدِ فِي سَبِيلِ اللَّهِ أَوْ الْقَائِمِ اللَّيْلَ الصَّائِمِ النَّهَارَ (Bukhari)
"Whoever strives [in support of] a widow or a poor person is like a mujahid in Allah's path or like one who stands the night [in prayer] and fasts the day."
The word (الْأَرْمَلَة) "armala" is usually used to mean widow. In fact it means any woman without husband and in economic difficulty whether or not she has ever been married and whether a husband left her by death or divorce.
"Miskeen" (poor person) means one who has something, but less than his/her needs. The same root can mean "weakness".
أَنَّ عَائِشَةَ زَوْجَ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ حَدَّثَتْهُ قَالَتْ جَاءَتْنِي امْرَأَةٌ مَعَهَا ابْنَتَانِ تَسْأَلُنِي فَلَمْ تَجِدْ عِنْدِي غَيْرَ تَمْرَةٍ وَاحِدَةٍ فَأَعْطَيْتُهَا فَقَسَمَتْهَا بَيْنَ ابْنَتَيْهَا ثُمَّ قَامَتْ فَخَرَجَتْ فَدَخَلَ النَّبِيُّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَحَدَّثْتُهُ فَقَالَ مَنْ يَلِي مِنْ هَذِهِ الْبَنَاتِ شَيْئًا فَأَحْسَنَ إِلَيْهِنَّ كُنَّ لَهُ سِتْرًا مِنْ النَّارِ (Bukhari)
Aisha reports that a woman came to her asking for help. She found nothing but a single date which she gave to her. She divided it between her two daughters and then left. The Prophet (sas) entered and she told him about it. He (sas) said, "Whoever takes responsibility for any of these daughters and is good to them will find them to be a barrier against Hellfire."
َأَنَا وَكَافِلُ الْيَتِيمِ فِي الْجَنَّةِ هَكَذَا وَأَشَارَ بِالسَّبَّابَةِ وَالْوُسْطَى وَفَرَّجَ بَيْنَهُمَا شَيْئًا (Bukhari)
"I and the custodian of an orphan will be in Paradise like this." (He signaled with his index and middle finger with a small gap between them."
The meaning is companionship and contact with the Prophet (sas) in Paradise.
It is narrated that Prophet Daud (as) said:
"Be to the orphan like a most merciful father. And know that just as how sow so shall you reap. How unpleasant is poverty after well-being. And, much worse than that is being astray after guidance. When you promise your companion anything, fulfill for him what you have promised. If you fail to do so, it will bring about enmity between you and him. Seek refuge in Allah from a companion who when you are in remembrance does not support you and when you are in forgetfulness does not remind you."