Charles H. Spurgeon on Psalms 61:2

Heart. The heart is here represented to us as being overwhelmed, or, as it is otherwise translated, "covered over; "it is smothered in, unable to perform its functions with proper action, unable to throw out the blood to the extremities, to give them needed vitality and power for necessary effort. When the action of the heart is paralysed, even temporarily, it will tell upon all the members, a chill there send its cold vibration through every limb; Satan knows this well, and so all his dealings are heart dealings, efforts to paralyse the very spring of life itself. This is precisely what we ourselves have experienced; we have partially felt death within us, we have felt a gradual numbing of our heart; a gradual diminution in the quickness of its beat; a gradual closing in, and pressure of a weight upon it, and this was the overwhelming process. Philip Bennett Power.