Romans 11:5-6

Thus, therefore, also in the zman hazeh, there has come into being a she'erit (remnant, remainder) in accordance with the bechirah (election) of chesed (free, unmerited favor or grace). But if on the mekor (basis) of chen v'chesed (unmerited favor, grace), then not on the mekor (basis) of ma'asim (works), vi-bahlt (since) otherwise chesed would no longer be chesed.