And thou hast well done that thou art come (su te kalōs epoiēsas paragenomenos). “And thou didst well in coming.” A regular formula for expressing thanks as in Phi 4:14; 3 Jo Phi 1:6; 2Pe 1:19. The participle completes the idea of kalōs poieō neatly. Cornelius commends Peter for his courage in breaking away from Jewish custom and takes no offence at the implied superiority of the Jews over the Gentiles. Cornelius and his circle of kinsmen and close friends are prepared soil for a new era in the history of Christianity. The Samaritans were now nominal Jews and the Ethiopian eunuch was a single case, but here Peter the chief apostle, not Philip the preaching deacon (evangelist), was involved. It was a crisis. Cornelius reveals an open mind for the message of God through Peter.
Commanded thee (prostetagmena soi). Perfect passive participle with the dative case (soi). Cornelius is a military man and he employs a military term (prostassō, old word to command). He is ready for orders from the Lord.