A.T. Robertson Commentary Acts 3:11

"And as he held Peter and John, all the people ran together unto them in the porch that is called Solomon`s, greatly wondering." — Acts 3:11 (ASV)

The Codex Bezae adds "as Peter and John went out."

As he held (κρατουντος αυτου). Genitive absolute of κρατεω, to hold fast, with accusative rather than genitive to get hold of (Acts 27:13). Old and common verb from κρατος (strength, force). Perhaps out of gratitude and partly from fear (Luke 8:38).

In the porch that is called Solomon's (επ τη στοα τη καλουμενη Σολομωντος). The adjective Stoic (στοικος) is from this word στοα (porch). It was on the east side of the court of the Gentiles (Josephus, Ant. XX. 9, 7) and was so called because it was built on a remnant of the foundations of the ancient temple. Jesus had once taught here (John 10:23).

Greatly wondering (εκθαμβο). Wondering out of (εκ) measure, already filled with wonder (θαμβους, verse 10). Late adjective. Construction according to sense (plural, though λαος singular) as in 5:16; 6:7; 11:1, etc.