Rashi on Exodus
לדרתיכם THROUGHOUT YOUR GENERATIONS — From here our Rabbis derived that it (the oil of anointment) was miraculously preserved in its entirety for the time to come (for the Messianic days) (Horayot 11b).
Sforno on Exodus
יהיה זה לי לדורותיכם, this oil of holy anointing for Me will last throughout your generations.