Acts 4:31

They had prayed. A constantly repeated exercise in the church (see chs. 1:14, 24; 2:42; 6:4).

The place was shaken. In view of further remarkable manifestations of the powerful presence of the Spirit of God, it may be concluded that this shaking was not an earthquake, but a supernatural experience. It was a renewal of the wonder of the day of Pentecost, but apparently without the appearance of the tongues of fire. Thus the Christians knew at once that the God of all nature to whom they had appealed (v. 24) was among them. In view of their direct need God gave them an immediate answer as a token that He had heard their prayers.

They were all filled. See on ch. 2:4. As on the day of Pentecost, the disciples knew again an infilling of the power of the Spirit. It gave them an assurance that they could speak with boldness the words they were commissioned to proclaim. The fact that the disciples had received the Spirit at Pentecost did not mean that further unction in times of special need might not be given. In fact, the primary bestowal of the Spirit had prepared them for such further outpourings. So also with the Christian today; the life begun in the Spirit, as signified by baptism, is dependent for its continuance upon constant communion and continually renewed supplies of spiritual grace.

They spake ... with boldness. Endowed with boldness by the power of the Spirit, for which they had prayed, from now on the apostles proclaimed the gospel whenever and wherever they found opportunity, refusing to be stopped by threats of any kind.