Charles Ellicott Commentary Acts 4:31

"And when they had prayed, the place was shaken wherein they were gathered together; and they were all filled with the Holy Spirit, and they spake the word of God with boldness." — Acts 4:31 (ASV)

The place was shaken...—The impression on the senses was, to that extent, a renewal of the wonder of the Day of Pentecost. However, in this instance, it was without the sign of the tongues of fire, which were the symbols of a gift imparted once for all. It was also, perhaps, without the special marvel of the utterance of the tongues. The disciples felt the power of the Spirit, the evidence of their senses confirming their inward, spiritual consciousness. This power came in the form for which they had made a special supplication: the power to speak with boldness the word they were commissioned to speak.