A.T. Robertson Commentary Acts 4:30

"while thy stretchest forth thy hand to heal; and that signs and wonders may be done through the name of thy holy Servant Jesus." — Acts 4:30 (ASV)

While thou stretchest forth thy hand (εν τω την χειρα εκτεινειν σε). Luke's favourite idiom, "In the stretching out (articular present active infinitive) the hand as to thee" (accusative of general reference), the second allusion to God's "hand" in this prayer (verse 28).

To heal (εις ιασιν). For healing. See verse 22.And that signs and wonders may be done (κα σημεια κα τερατα γινεσθα). Either to be taken as in the same construction as εκτεινειν with εν τω as Revised Version has it here or to be treated as subordinate purpose to εν τω εκτεινειν (as Knowling, Page, Wendt, Hackett). The latter most likely true. They ask for a visible sign or proof that God has heard this prayer for courage to be faithful even unto death.