2 Timothy 4:19 2 Timothy 4 2 Timothy 4:18-20 "Salute Prisca and Aquila, and the household of Onesiphorus."These two must be precious to him for him to have used the familiar, or petname.
Two other refernces which give the flavor of his regard and some inkling of their function:
Romans 16:3 Romans 16 Romans 16:2-4 "Greet Priscilla and Aquila my helpers in Christ Jesus:"
1 Corinthians 16:19 1 Corinthians 16 1 Corinthians 16:18-20 "The churches of Asia salute you. Aquila and Priscilla salute you much in the Lord, with the church that is in their house."