23 When they were released, they went to their friends and reported what the chief priests and the elders had said to them. 24 And when they heard it, they lifted their voices together to God and said, “Sovereign Lord, who made the heaven and the earth and the sea and everything in them, 25 who through the mouth of our father David, your servant, said by the Holy Spirit, “‘why did the Gentiles rage, and the peoples plot in vain?
26 The kings of the earth set themselves, and the rulers were gathered together, against the Lord and against his Anointed’—
27 for truly in this city there were gathered together against your holy servant Jesus, whom you anointed, both Herod and Pontius Pilate, along with the Gentiles and the peoples of Israel, 28 to do whatever your hand and your plan had predestined to take place. 29 And now, Lord, look upon their threats and grant to your servants[f] to continue to speak your word with all boldness, 30 while you stretch out your hand to heal, and signs and wonders are performed through the name of your holy servant Jesus.” 31 And when they had prayed, the place in which they were gathered together was shaken, and they were all filled with the Holy Spirit and continued to speak the word of God with boldness. (Acts 4:23-31)
Why all this opposition? What to say? Why was it? It was all foretold as part of God’s ancient plan; and the details truly and actually happened. And He had the power to control it.
So the disciples pray for courage to continue in obediently fulfilling God’s purposes and commands. The house shakes as in an earthquake and their prayer is answered.