Abdul-Aziz bin Marwan wrote to Ibn Umar, "Inform me of your needs."Ibn Umar wrote back to him, "The Messenger of Allah ﷺ used to say, 'The upper hand is better than the lower hand, and begin with those whom you support.' I am not asking you for anything, nor will I refuse a provision that Allah grants me through you."
حدثنا إسحاق بن يوسف عن سفيان عن ابن عجلان
كتب عبد العزيز بن مروان إلى ابن عمر أن ارفع إلي حاجتك قال فكتب إليه ابن عمر أن رسول الله ﷺ كان يقول إن اليد العليا خير من اليد السفلى وابدأ بمن تعول ولست أسألك شيئا ولا أرد رزقا رزقنيه الله منك
Its isnad is sahih. Sufyan is Thawri. Ibn Ajlan is Muhammad bin Ajlan. The raised portion of this hadith was mentioned by Suyuti in Jami Saghir 10027, who attributed it to Ahmad and Tabarani, and its commentator Munawi quoted Haythami as saying, "Its narrators are the narrators of the sahih." I searched at length for it in Majma al-Zawaid but did not find it.Bukhari 3:235 narrated it through Ayub and Malik, from Nafi, from Ibn Umar, as a raised hadith, "The upper hand is better than the lower hand. The upper hand is the one that gives, and the lower hand is the one that asks." Muslim also narrated it, 1:282, through Malik from Nafi, and it was also narrated by Abu Dawud and Nasai, as mentioned in Targheeb wal-Tarheeb 2:10. See also what has already passed in the Musnad of Ibn Masud, 4261.