Here are some of Brother William Branham's quotes that can encourage you to join in prayer:

1. "Prayer changes things. It opens the doors to God’s blessings and makes a way where there seems to be no way."

2. "Let us all gather in prayer, believing, with faith in our hearts, that God will hear and answer us."

3. "There’s power in prayer. And when the people of God come together in unity, there’s nothing impossible with God."

4. "If we could just get down on our knees and sincerely pray, the world would be a different place."

5. "The Bible said, 'If two or three agree, asking anything in my name, it shall be done.' That’s the reason I ask you to join in prayer, believing together."

6. "The greatest thing in the world is prayer. Prayer is the key that unlocks the doors to heaven."

7. "If the people would unite and pray, the power of God would come down in mighty revival."

These quotes can serve as an encouragement for others to join in prayer and seek God's help together.