Another interpretation: since its commandment is to bring from the moist, from where that if one did not find from the moist he may bring from the dried? Scripture teaches by saying "you shall bring."
Bringing the Omer From Fresh or From Dried Grain
Yalkut Shimoni on Torah 455:3
דָּבָר אַחֵר לְפִי שֶׁמִּצְוָתוֹ לְהָבִיא מִן הַלַּח, מִנַּיִן שֶׁאִם לֹא מָצָא מִן הַלַּח יָבִיא מִן הַיָּבֵשׁ, תַּלְמוּד לוֹמַר "תַּקְרִיב".