Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: "I loved Umar (may Allah be pleased with him) so much that I felt fear of Allah. If I came to know that even a dog loved Umar (may Allah be pleased with him), I would love it too, and I wished that I had been a servant of Umar (may Allah be pleased with him). Everything felt his loss, even the thorny trees. His emigration was a help, and his rule was a mercy."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 8782