That's right, except in English you would not use "the" in this case of "food." And technically, 내리다 means "come down." So, "From heaven food like rain will come down." (And perhaps you know that -을 in 양식을 is an object marker: it shows that the word 양식 is a direct object.)
I still have a question: Why does the verb "come down" take an object-noun? Where is the (auxiliary-)verb corresponding to "let" or "make/cause to"? I'm such a beginner that I fail to know the ABC of the Korean grammar.
Right, it's trickier than it appears. In the construction "it is raining," you have "비가 내리다." (lit., "The rain is falling/coming down.") "비" takes a subject marker in that case ("가").
The "topic" of the sentence (what English speakers would think of as the subject) is implied. God is speaking, so to make the main subject (=topic) explicit, you would have "나는 하늘에서 양식을 비같이 내리리니...."
You didn't ask this, but the second "리" in "내리리다" refers to future tense.
Finally, I'm not 100% sure about my answer to this part, but I think the "make/cause to" idea is implied by the object marker on 양식.