ذَٲلِكَ ٱلَّذِى يُبَشِّرُ ٱللَّهُ عِبَادَهُ ٱلَّذِينَ ءَامَنُواْ وَعَمِلُواْ ٱلصَّـٰلِحَـٰتِ‌ۗ قُل لَّآ أَسۡـَٔلُكُمۡ عَلَيۡهِ أَجۡرًا إِلَّا ٱلۡمَوَدَّةَ فِى ٱلۡقُرۡبَىٰ‌ۗ وَمَن يَقۡتَرِفۡ حَسَنَةً۬ نَّزِدۡ لَهُ ۥ فِيہَا حُسۡنًا‌ۚ إِنَّ ٱللَّهَ غَفُورٌ۬ شَكُورٌ (٤٢:٢٣)

That is the good news that Allah gives to His slaves who believed and did righteous deeds. Say, "I do not ask you any fee for it, except the love of kinship." And whoever performs a good act, for him We will increase goodness therein. Surely Allah is Most-Forgiving, Very Appreciative (42:23).

Correlating Hadith

Ibn Abbas narrates from the Messenger of Allah, “When the verse was revealed: 'Say, "I do not ask you any fee for it, except the love of kinship"' [42:23], they said, ‘O Messenger of Allah, who are they, those we are commanded to love?’ He [the Prophet] said: '[Imam] Ali, [Sayyida] Fatima, and their children."

رّسول (صلی الله علیه و آله)- عن إبن‌عبّاس (رحمة الله علیه) لَمَّا (سلام الله علیها) نَزَلَتْ قُلْ لا أَسْئَلُکُمْ عَلَیْهِ أَجْراً الْآیَهًَْ قَالُوا یَا رسول الله (صلی الله علیه و آله) مَنْ هَؤُلَاءِ الَّذِینَ أُمِرْنَا بِمَوَدَّتِهِمْ قَالَ علِيٌّ (علیه السلام) وَ فَاطِمَةَْ (سلام الله علیها) وَ وُلْدُهُمَا

Sources 

Bihar al-Anwar, vol. 23, pg. 10 and vol. 31, pg. 210; Shawahid al-Tanzil, vol. 2, pg. 194.

تفسیر اهل بیت علیهم السلام ج13، ص602 / بحارالانوار، ج23، ص229/ فرات الکوفي، ص389