to not delete both columns A and B on that row must contain the strings

set lastrow = cells(rows.count,1).End(xlup).row
for i = lastrow to 1 step -1
 if instr(1,cells(i,1),"Whse: ", vbTextCompare) > 0 and _
   instr(1,cells(k,2),"Source: ", vbTextCompare) > 0 then
      ' do nothing
 else
       if rng is nothing then
          set rng = cells(i,1)
        else
          set rng = union(rng,cells(i,1))
        end if  
   end if
Next
if not rng is nothing then
 rng.Entirerow.Delete
End if

or
If either contains the specific string, then don't delete

set lastrow = cells(rows.count,1).End(xlup).row
for i = lastrow to 1 step -1
 if instr(1,cells(i,1),"Whse: ", vbTextCompare) > 0 or _
   instr(1,cells(k,2),"Source: ", vbTextCompare) > 0 then
      ' do nothing
 else
       if rng is nothing then
          set rng = cells(i,1)
        else
          set rng = union(rng,cells(i,1))
        end if  
   end if
Next
if not rng is nothing then
 rng.Entirerow.Delete
End if