Jesus was hanging on the cross, dying. Who expects a dying man to "come into" a kingdom? Those who have kingdoms relinquish them at death yet the robber, who had mocked Jesus just a bit before**, suddenly realized Jesus was no ordinary man. This man, Jesus, would gain a kingdom with his death. Curious, that.
Regardless of how the insight came to him, it took a great deal of faith to make that request to a dying "criminal."
God, I want to have faith like that thief.