Book 20, Number 20.76.261:

Yahya related to me from Malik that Yahya ibn Said heard Muhammad ibn Yahya ibn Habban mentioning that a certain man passed Abu Zharr at ar-Rabazha (which was about 30 miles from Madina) and Abu Zharr asked him, "Where are you heading to?" and he replied, "I am intending to do hajj." Abu Zharr questioned, "Has anything else brought you out?" and he said, "No," so Abu Zharr said "Resume what you are doing wholeheartedly."

The man related, "I went on till I came to Makka and I stayed as long as Allah willed. Suddenly, one time, I was with a crowd of people thronging about a man and I pushed through the people to him and it was the old man that I had come across at ar-Rabazha. When he saw me, he recognized me and said, 'Ah, you have done what I told you.' "