Acts 1:14
With one accord they all continued in prayer, along with the women and Mary the mother of Jesus, and with His brothers.

Joel 2:15-17
Blow the ram’s horn in Zion, consecrate a fast, proclaim a sacred assembly. / Gather the people, sanctify the congregation, assemble the aged, gather the children, even those nursing at the breast. Let the bridegroom leave his room, and the bride her chamber. / Let the priests who minister before the LORD weep between the portico and the altar, saying, “Spare Your people, O LORD, and do not make Your heritage a reproach, an object of scorn among the nations. Why should they say among the peoples, ‘Where is their God?’”

Matthew 18:20
For where two or three gather together in My name, there am I with them.”

Nehemiah 9:1-3
On the twenty-fourth day of the same month, the Israelites gathered together, fasting and wearing sackcloth, with dust on their heads. / Those of Israelite descent separated themselves from all the foreigners, and they stood and confessed their sins and the iniquities of their fathers. / While they stood in their places, they read from the Book of the Law of the LORD their God for a quarter of the day, and they spent another quarter of the day in confession and worship of the LORD their God.

Acts 12:12
And when he had realized this, he went to the house of Mary the mother of John, also called Mark, where many people had gathered together and were praying.

Ezra 8:21-23
And there by the Ahava Canal I proclaimed a fast, so that we might humble ourselves before our God and ask Him for a safe journey for us and our children, with all our possessions. / For I was ashamed to ask the king for an escort of soldiers and horsemen to protect us from our enemies on the road, since we had told him, “The hand of our God is gracious to all who seek Him, but His great anger is against all who forsake Him.” / So we fasted and petitioned our God about this, and He granted our request.

Acts 4:31
After they had prayed, their meeting place was shaken, and they were all filled with the Holy Spirit and spoke the word of God boldly.

1 Samuel 7:5-6
Then Samuel said, “Gather all Israel to Mizpah, and I will pray to the LORD on your behalf.” / When they had gathered at Mizpah, they drew water and poured it out before the LORD. On that day they fasted, and there they confessed, “We have sinned against the LORD.” And Samuel judged the Israelites at Mizpah.

Matthew 21:22
If you believe, you will receive whatever you ask for in prayer.”

Acts 16:25
About midnight Paul and Silas were praying and singing hymns to God, and the other prisoners were listening to them.

1 Kings 8:22-23
Then Solomon stood before the altar of the LORD in front of the whole assembly of Israel, spread out his hands toward heaven, / and said: “O LORD, God of Israel, there is no God like You in heaven above or on earth below, keeping Your covenant of loving devotion with Your servants who walk before You with all their hearts.

Philippians 4:6
Be anxious for nothing, but in everything, by prayer and petition, with thanksgiving, present your requests to God.

Psalm 106:47
Save us, O LORD our God, and gather us from the nations, that we may give thanks to Your holy name, that we may glory in Your praise.

Luke 18:1
Then Jesus told them a parable about their need to pray at all times and not lose heart:

Isaiah 56:7
I will bring them to My holy mountain and make them joyful in My house of prayer. Their burnt offerings and sacrifices will be accepted on My altar, for My house will be called a house of prayer for all the nations.”