From Sahih Bukhari (Hadith 1468):
Narrated Abu Huraira:Allah's Messenger (ﷺ) ordered (a person) to collect Zakat, and that person returned and told him that Ibn Jamil, Khalid bin Al-Walid, and `Abbas bin `Abdul Muttalib had refused to give Zakat." The Prophet said, "What made Ibn Jamil refuse to give Zakat though he was a poor man, and was made wealthy by Allah and His Apostle ? But you are unfair in asking Zakat from Khalid as he is keeping his armor for Allah's Cause (for Jihad). As for `Abbas bin `Abdul Muttalib, he is the uncle of Allah's Apostle (ﷺ) and Zakat is compulsory on him and he should pay it double
Reference: Bukhari 1468