Bonds payable

HI guys,

please would you help me out getting more details on the bonds payable accoutning process, my query is as follow:

-we recognise the bonds payable at the sale proceeds (i.e. PV of the face value discounted at effective mkt rate) and this includes the interests payments and principal. Say the bond is issued at par, since we recognise each perio’s interest expense, the liability shoudl reflect the decrease of this interest expense now paid but from what i understood, the liability should retain the initial carried amount till the end?

i am sure i am missing something obvious so sorry if this is ridiculous- thanks