Exegesis:

kai autoi ‘and they,’ indicating change of subject.

proskunēsantes auton ‘after worshipping him,’ cf. on 4.7.

meta charas megalēs ‘with great joy.’ meta with genitive here expresses accompanying emotions.

(V. 53) kai ēsan dia pantos en tō hierō ‘and they were constantly in the temple.’ dia pantos scil. chronou, lit. ‘during all the time,’ ‘constantly.’ For hieron cf. on 2.27.

eulogountes ton theon ‘praising God,’ cf. on 1.64 and 42.

Translation:

For to worship see on 4.17; for with great joy, or, ‘very joyfully,’ cf. on 8.13.

(V. 53) Were continually in the temple, or, “spent all their time in the temple” (New English Bible), or, stated negatively, ‘did not cease being (or, stayed without interval) in the temple’ (Sundanese, Tae’). The expression is hyperbolical, like the comparable one in 2.37.

Blessing God, i.e. praising God, see on 1.42, sub (2).