A person must train and accustom himself to pray in a low voice and to cry out silently, even when reciting the songs of praise. Nonetheless, he should say the words, whether of prayer or of Torah, with all his might, as the verse states,⁵⁴ “All my bones⁵⁵-כל עצמותי-All my bones also means “My very essence.” shall say, ‘HaShem, who is like You.’” A cry that results from true adhesion to HaShem is a silent cry.⁵⁶) and divine inspiration during prayer, see Kuntres HaHitpaalut of Rabbi DovBer of Lubavitch, translated as Divine Inspiration.

footnotes: ⁵⁴ Psalms 35:10 ⁵⁵ Kol Atzmotai ⁵⁶ For an extensive explanation of the varying levels of adhesion (Dveikut