A more thorough explanation:

Definition: A clog on the equity of redemption is an agreement or condition that prevents a mortgagor (borrower) from getting back their property free from any encumbrance (legal claim) upon paying the debt or fulfilling the obligation for which the security was given.

Equity of Redemption: The equity of redemption is the right of a mortgagor in default to recover their property before a foreclosure sale by paying the principal, interest, and other costs that are due. This means that a mortgagor has the right to reimburse the mortgagee (lender) and cure the default until the foreclosure sale. In some jurisdictions, the mortgagor also has a statutory right to redeem within six months after the foreclosure sale, and the mortgagor becomes entitled to any surplus from the sale proceeds above the amount of the outstanding mortgage.

Example: Let's say John took out a mortgage to buy a house. He fell behind on his payments, and the lender threatened to foreclose on the property. John managed to come up with the money to pay off the debt, but the lender refused to release the property unless John paid an additional fee. This fee is a clog on the equity of redemption because it prevents John from getting back his property free from any encumbrance upon paying the debt.

Explanation: The example illustrates how a clog on the equity of redemption can prevent a mortgagor from recovering their property even after paying off the debt. In this case, the lender is imposing an additional fee that is not related to the debt or obligation for which the security was given. This fee is a clog on the equity of redemption because it prevents John from exercising his right to redeem the property and get it back free from any encumbrance.