The words holy
and righteous
occur together rather frequently in Greek literature. The two words (or their related nouns and adjectives) occur together as a unit thirteen times in the Septuagint, four times in the New Testament (Luke 1:75; Ephesians 4:24; 1 Thessalonians 2:10; Titus 1:8), six times in Josephus, nineteen times in Philo, and seven times in the Apostolic Fathers.
10 You are witnesses, and God also, how holy and righteous and blameless was our conduct toward you believers.