Christian music echoed from the steps of City Hall as participants sang and prayed to mark this National Day of Prayer.
Governor Rick Perry said, "The lesson for us is to seek God's wisdom, heed his voice."
"I am so grateful that we have the privilege to worship God," said participant Jeannie Satterwite. "You can't do that just everywhere. God bless America."
While the freedom of religion is never in question, there is a growing debate about whether a National Day of Prayer violates the constitution. Civil rights attorney Randall Kallinen says government shouldn't sanction religious events.
"You cannot promote any religion," Kallinen said. "If there was a mixture of Muslims and Christians, that still would be promoting religion which the constitution forbids."
"God is being taken out of everything, and he's the reason why we are even here," said prayer participant Patricia King.
Although not specified, the gathering in downtown Houston was focused on the Christian faith, something that worried Dianne Davis.
She said, "They're sending a message that everyone's excluded except for Christians, and I'm part Jewish."
But those who prayed say this isn't about one particular religion or the constitution. They simply believe it's the right thing to do.
"I don't see any war out here," said prayer participant Morris Ellis. "It's Christian-centric, OK, but I don't see people fighting."