Trigger AccountLockRecord on Account (before insert, after update) {

For (Account soAccount: Trigger.New){

     List<Account> lstAccount = new List<Account>();

    If (soAccount.ISLock__c = True){
        system.debug(logginglevel.debug, 'DEBUG: lOCK' );
         lstAccount.add(soAccount);

        Approval.LockResult[] lrList = Approval.lock(lstAccount, false);

    } else If (soAccount.ISLock__c = False){

        system.debug(logginglevel.debug, 'DEBUG: uNlOCK' );
          lstAccount.add(soAccount);

        Approval.UnlockResult[] lrList1 = Approval.unlock(lstAccount);

    }
   }

 }