A pensioner threatened a mental health worker during a campaign of harassment against her, Lincoln Crown Court was told.
George Calladine had been given support and help to find accommodation by the woman who was working with the Nomad Trust in the city.
On one occasion the victim had to lock herself in a room for her own safety after Calladine confronted her at St Mary le Wigford Church.
Andrew Scott, prosecuting, said Calladine went on to make threats to other people including a churchwarden that he was going to kill the woman.
And later he told a social worker: "I know her car. I'll blow it up. I'll kill her. I want her dead."
When he was arrested he told officers "I haven't done anything wrong." He said he would not have harmed the woman.
Calladine, 68, of Risby Green, Lincoln, admitted harassment between April 17 and June 7 this year. He was jailed for 19 months. He also admitted breach of a suspended jail sentence imposed for threatening hospital staff with a bottle and was given a nine-week consecutive jail term.
Judge Michael Heath imposed an indefinite restraining order banning Calladine from contacting the woman and from entering St Mary le Wigford Church and its surrounding grounds.
Christopher Geeson, defending, said: "He has been in custody for two months. It has given him time to sober up. He is somebody who needs help."