Acts 12:5 (Read all of Acts 12)
Peter therefore was kept in prison: but prayer was made without ceasing of the church unto God for him.
Romans 1:9 (Read all of Romans 1)
For God is my witness, whom I serve with my spirit in the gospel of his Son, that without ceasing I make mention of you always in my prayers;
1 Thessalonians 5:17 (Read all of 1 Thessalonians 5)
Pray without ceasing.
2 Timothy 1:3 (Read all of 2 Timothy 1)
I thank God, whom I serve from my forefathers with pure conscience, that without ceasing I have remembrance of thee in my prayers night and day;