Why was Darwin hesitant about publishing his theory of evolution by natural selection, and why did he decide to finally publish his work?

Charles Darwin kept his theory of evolution to himself for twenty-one years! He was hesitant to publish his findings because because he was afraid of what others would think. Many people wouldn't agree to his theory because it went against the Christian faith by saying that God did not create each species separately; that nature itself did, and continues to create new species. Darwin decided to publish his theory of evolution when he was approached by another naturalist: Alfred Wallace. Mr. Wallace asked Darwin to review his paper on evolution by natural selection, so Charles Darwin hurried up his refining on his book, The Origin of Species, and published it in 1859 to further other scientists' knowledge, and to receive primary credit before anyone else did.