Names related to christ/christianity?

its for characters of the book i intend to write, the protagonist is a teen girl, Gloria Johnson. people call her Glory. her family is very religious and her name Glory comes from Glory to christ. she has 2 younger sisters Faith Johnson (Faith in Christ) her youngest sister needs a name but im stuck any ideas please help. is Mercy a religious word (Mercy to the Lord). also do you think is should be Faith as the eldest sister and Glory as the second sister. thanks x