Sahih Bukhari Volume 007, Book 070, Hadith Number 576.
Narrated By Qais bin Abi Hazim : We went to pay a visit to Khabbab (who was sick) and he had been branded (cauterized) at seven places in his body. He said, "Our companions who died (during the lifetime of the Prophet) left (this world) without having their rewards reduced through enjoying the pleasures of this life, but we have got (so much) wealth that we find no way to spend It except on the construction of buildings Had the Prophet not forbidden us to wish for death, I would have wished for it.' We visited him for the second time while he was building a wall. He said, A Muslim is rewarded (in the Hereafter) for whatever he spends except for something that he spends on building."