21 Grk “And they.” Because of the difference between Greek style, which often begins sentences or clauses with “and,” and English style, which generally does not, καί (kai) has not been translated here.
22 Grk “walking in” (an idiom for one’s lifestyle). The description of Zechariah and Elizabeth as following … blamelessly was not to say that they were sinless, but that they were faithful and pious. Thus a practical righteousness is meant here (Gen 6:8; Deut 28:9).
23 The predicate adjective has the effect of an adverb here ( §243).

In other versions

And they were both righteous before God, walking blamelessly in all the commandments and statutes of the Lord.

Both of them were righteous in the sight of God, observing all the Lord’s commands and decrees blamelessly.

Both were righteous in God’s sight, living without blame according to all the commands and requirements of the Lord.

Zechariah and Elizabeth were righteous in God’s eyes, careful to obey all of the Lord’s commandments and regulations.

And they were both righteous in the sight of God, living blamelessly in all the commandments and regulations of the Lord.

And they were both righteous before God, walking in all the commandments and ordinances of the Lord blameless.

Public Domain