The Greek verb ekdiegeomai is an intensive compound of ek (out/thoroughly) and diegeomai (to narrate/explain), meaning to narrate fully, declare thoroughly, or relate in detail. It appears twice in the NT (Acts 13:41; 15:3), both times describing the complete telling of God's mighty works.
Both NT occurrences of ekdiegeomai relate to the proclamation of God's saving works. In Acts 13:41, Paul quotes Habakkuk warning those who refuse to believe the work God is doing through Christ — a work so extraordinary it defies full telling. In Acts 15:3, Paul and Barnabas pass through Phoenicia and Samaria "telling in full" the conversion of the Gentiles, causing great joy. The verb captures the compulsion of gospel proclamation — the good news is so magnificent that it demands thorough, complete declaration. The missionary impulse is rooted in the desire to ekdiegeomai what God has done.