The Jews practiced Tishlikh (tish-lick) on Yom Kippur the Day of Atonement.

They would cast bread (sin) upon the sea and watch for the fish to eat it and take it away.

Perhaps that is what Peter was implying, that Jesus as the Bread of Life, who takes away our sins as we “cast our cares upon Him.”

Maybe that is where the expression “cast your cares upon the waters” comes from.   Interesting.

Volume 14; June 9, 1922
…Afterwards He told me:  “My beloved, how much Love I feel toward you.  All the Love that I should give to others, and that they refuse, I centralize in you.  In you I hear the Echo of My Creative Word:  ‘Let Us make man in Our Image and Likeness’, and I see the Fulfillment of it.  Ah! Our Will alone will make man return to his First Origin.  Our Will will cast all the Divine Impressions into the human will, and overwhelming one will within the Other, It will carry him on Its Wings into the Arms of his Creator – not ugly, as sin rendered him, but pure and beautiful, and similar to his Creator.”…