Upon my heart – Ask the Rabbi
Q. Why does the Shema tell us to place God’s words “on”, not “in” our hearts?
A. The Kotzker Rebbe said that people’s hearts are not always open to inspiration, but if the Divine words are on top of our heart they will be ready to enter it the moment it becomes receptive.
The Rebbe of Kalisch said that the Hebrew al need not mean “upon” but can denote “above”. If one’s heart desires inappropriate things the Divine words should be above them and exercise firm control.