וְהָיָה֙ כִּ֣י הִרְבְּתָ֔ה לְהִתְפַּלֵּ֖ל לִפְנֵ֣י יְהוָ֑ה וְעֵלִ֖י שֹׁמֵ֥ר אֶת־פִּֽיהָ׃
And it came to pass, as she prayed long before the LORD, that Eli watched her mouth.
Read kabbalistic (mystical) interpretation of I Samuel 1:12: and classical mystical sources.