Ps 16 7 I will praise the LORD , who counsels me;  even at night my heart instructs me. 8 I have set the LORD always before me. Because he is at my right hand,  I will not be shaken. 9 Therefore my heart is glad and my tongue rejoices; my body also will rest secure,

My heart instructs me. His thoughts check and guide him like the reins of a horse, The right hand is the control that he pronounces in the law,covenants, curses, statutes, promises and decrees.We pronounce Christ eternal pronouncements. The mind with the knowledge of the pronouncements controls the tongue which affects the health of the body,.