have Jesus in one's heart

Possibly a reference to Ephesians 3:14 and 17 of the Bible (King James Version, spelling modernized): “For this cause I bow my knees unto the Father of our Lord Jesus Christ, […] That Christ may dwell in your hearts by faith, […]”.[1]

• (Received Pronunciation) IPA^(key): /həv ˈd͡ʒiːzəs ɪn wʌnz ˈhɑːt/
• (General American) IPA^(key): /həv ˈd͡ʒizəs ɪn wʌnz ˈhɑɹt/
• Rhymes: -ɑː(ɹ)t
• Hyphenation: have Jes‧us in one’s heart

have Jesus in one's heart (third-person singular simple present has Jesus in one's heart, present participle having Jesus in one's heart, simple past and past participle had Jesus in one's heart)

1. (intransitive, Christianity, idiomatic) To be a firm believer in the Christian faith.

• When referring to more than one person, the phrase can be used with a plural form of heart, for example, “they have Jesus in their hearts”.