Benjamin Field, 28, used a white marker pen to leave biblical messages for 83-year-old Ann Moore-Martin as part of a campaign of “gaslighting”.
Field – 57 years her junior – sent Miss Moore-Martin letters, postcards and poems speaking of his love and discussing marriage during a year-long seduction.
The church warden, who admits being in a fraudulent relationship with Miss Moore-Martin, also wrote messages urging her to give him £27,000 towards the cost of a dialysis machine, purportedly for his seriously ill brother Tom, 24.
Oxford Crown Court heard that Miss Moore-Martin, who never married or had children, later changed her will to leave her home in Maids Moreton, Buckinghamshire, to Field but changed her mind shortly before she died in May 2017 and alleged Field had poisoned her.
The jury was told Field had taken photographs of the messages, which were later recovered from his phone following his arrest.
The first message, illustrated with a cross, said: “All that you give him, He will return, Ten fold.”
A second message said: “Your intentions are holy, Your work is not yet done, Take care and complete the task, Given to you by the Lord.”
A third said: “Your soul will proceed directly to heaven, Her soul to joy; his to perfection, This good you will can never be undone. Peace is yours in me, your Lord. Amen.”
A final message said: “Pray for Ben, Ben loves you.”