put backbone into (one)
To embolden one; to give one courage or determination. All of their encouragement put backbone into me to tell the boss we wanted better working conditions. She was afraid of changing careers, but the thought of staying in this dead end job forever put backbone into Janet.
put backbone into someone
encourage someone to behave resolutely. As a metaphor for ‘firmness of character’, backbone dates from the mid 19th century.
1998 Spectator There is a widespread belief that if only Mrs Thatcher had still been in No. 10, she would have put backbone into Bush and got rid of Saddam .