Albert Barnes Commentary 1 Corinthians 10:3

"and did all eat the same spiritual food;" — 1 Corinthians 10:3 (ASV)

And did all eat the same spiritual meat. That is, manna (Exodus 16:15, 35; Nehemiah 9:15, 20).

The word meat here is used in the old English sense, meaning food in general. They lived on manna.

The word spiritual here evidently denotes that which was given by the Spirit, or by God. It was the result of His miraculous gift, was not produced in the ordinary way, and was not the gross food on which people are usually supported.

It had an excellency and value because it was the immediate gift of God, and is thus called angel's food (Psalms 78:25). Josephus calls it "Divine and extraordinary food" (Antiquities iii.1).

In the language of the Scriptures, whatever is distinguished by excellence, is the immediate gift of God, and is unlike what is gross and of earthly origin, is called spiritual to denote its purity, value, and excellence. (1 Corinthians 3:1; 1 Corinthians 15:44, 46; Ephesians 1:3).

Paul's idea here is that all the Israelites were nourished and supported in this remarkable manner by food given directly by God, and that they all, therefore, had evidence of Divine protection and favour, and were all under His care.