A.T. Robertson Commentary Acts 1:17

"For he was numbered among us, and received his portion in this ministry." — Acts 1:17 (ASV)

Was numbered (κατηριθμενος ην). Periphrastic past perfect passive indicative of καταριθμεω, old verb, but here only in the N.T. (perfective use of κατα).

Received his portion (ελαχεν τον κληρον). Second aorist active indicative of λαγχανω, old verb, to obtain by lot as in Lu 1:9; John 19:24, especially by divine appointment as here and 2 Peter 2:1. Κληρος also means lot, an object used in casting lots (Acts 1:26), or what is obtained by lot as here and 8:21, of eternal salvation (Acts 26:18; Colossians 1:12), of persons chosen by divine appointment (1 Peter 5:3). From this latter usage the Latin cleros, clericus, our clergy, one chosen by divine lot. So Peter says that Judas "obtained by lot the lot of this ministry" (διακονιας) which he had when he betrayed Jesus. The Master chose him and gave him his opportunity.