I, brethren, could not speak unto you as unto spiritual - This is a continuation of the preceding discourse. See the notes on 1 Corinthians 2:14, 1 Corinthians 2:15 (note), and 1 Corinthians 2:16 (note).

But as unto carnal - Σαρκικοις, Persons under the influence of fleshly appetites; coveting and living for the things of this life.

Babes in Christ - Just beginning to acquire some notion of the Christian religion, hut as yet very incapable of judging what is most suitable to yourselves, and consequently utterly unqualified to discern between one teacher and another; so that your making the distinctions which you do make, so far from being a proof of mature judgment, is on the contrary a proof that you have no right judgment at all; and this springs from your want of knowledge in Divine things.

as unto spiritual.

1 Corinthians 2:6,15 However, we speak wisdom among them that are perfect: yet not the wisdom of this world, nor of the princes of this world...

Galatians 6:1 Brothers, if a man be overtaken in a fault, you which are spiritual, restore such an one in the spirit of meekness...

as unto carnal.

1 Corinthians 3:3,4 For you are yet carnal: for whereas there is among you envying, and strife, and divisions, are you not carnal, and walk as men...

1 Corinthians 2:14 But the natural man receives not the things of the Spirit of God: for they are foolishness to him: neither can he know them...

Matthew 16:23 But he turned, and said to Peter, Get you behind me, Satan: you are an offense to me: for you mind not the things that be of God...

Romans 7:14 For we know that the law is spiritual: but I am carnal, sold under sin.

babes.

1 Corinthians 14:20 Brothers, be not children in understanding: however, in malice be you children, but in understanding be men.

Ephesians 4:13,14 Till we all come in the unity of the faith, and of the knowledge of the Son of God, to a perfect man...

1 John 2:12 I write to you, little children, because your sins are forgiven you for his name's sake.

God's Fellow-Workers
'Labourers together with God.'--1 COR. iii. 9. The characteristic Greek tendency to factions was threatening to rend the Corinthian Church, and each faction was swearing by a favourite teacher. Paul and his companion, Apollos, had been taken as the figureheads of two of these parties, and so he sets himself in the context, first of all to show that neither of the two was of any real importance in regard to the Church's life. They were like a couple of gardeners, one of whom did the planting, and …
Alexander Maclaren—Romans, Corinthians (To II Corinthians, Chap. V)

The Christian Church
Scriptures references: 1 Corinthians 3:11; 3:6-9; Colossians 1:18; Acts 2:47; Ephesians 5:23-27; Matthew 16:16,18; 18:17; Acts 5:11,12; 13:1,2; 14:23; 16:5; 1 Corinthians 11:18-34; 12:28-31; 1 Thessalonians 1:1; 2:14; 1 Timothy 3:15; Hebrews 12:22,23; Revelation 1:4,11,20; 2:7,11; 22:16; 22:12-15,17. THE FOUNDATION OF THE CHURCH What is the Christian Church?--One of the best definitions is as follows: "The church consists of all who acknowledge the Divine Lord, Jesus Christ, the blessed Saviour …
Henry T. Sell—Studies in the Life of the Christian

Carnal Christians.
1 Corinthians 3:1.--And I, brethren, could not speak unto you as unto spiritual, but as unto carnal. The apostle here speaks of two stages of the Christian life, two types of Christians: "I could not speak unto you as unto spiritual, but as unto carnal, even as unto babes in Christ." They were Christians, in Christ, but instead of being spiritual Christians, they were carnal. "I have fed you with milk, and not with meat, for hitherto ye were not able to bear it, neither yet are ye able, for ye are …
Andrew Murray—The Master's Indwelling