Mosiah 24:12

And it came to pass that Alma and his people did not raise their voices to the Lord their God, but did pour out their hearts to him; and he did know the thoughts of their hearts.

Alma and his people didn’t pray out loud to the Lord their God anymore. But they prayed in their hearts. God knew their thoughts.

So Alma and his people stopped praying aloud. Instead, they poured out their hearts to the Lord silently. And he knew the thoughts of their hearts.