A.T. Robertson Commentary Acts 10:2

"a devout man, and one that feared God with all his house, who gave much alms to the people, and prayed to God always." — Acts 10:2 (ASV)

Devout (ευσεβης). Old word from ευ (well) and σεβομα (to worship, to reverence), but rare in the N.T. (Acts 10:2,7; 2 Peter 2:1). It might refer to a worshipful pagan (Acts 17:23, σεβασματα, objects of worship), but connected with "one that feared God" (φοβουμενος τον θεον) Luke describes "a God-fearing proselyte" as in 10:22,35. This is his usual term for the Gentile seekers after God (13:16, 26; 17:4,17, etc.), who had come into the worship of the synagogue without circumcision, and were not strictly proselytes, though some call such men "proselytes of the gate" (cf. Acts 13:43); but clearly Cornelius and his family were still regarded as outside the pale of Judaism (10:28,34; 11:1,8; 15:7). They had seats in the synagogue, but were not Jews.

Gave much alms (ποιων ελεεμοσυνας πολλας). Doing many alms (the very phrase in Mt 6:2), a characteristic mark of Jewish piety and from a Gentile to the Jewish people.

Prayed (δεομενος). Begging of God. Almsgiving and prayer were two of the cardinal points with the Jews (Jesus adds fasting in his picture of the Pharisee in Mt 6:1-18).