John Montagu was the fourth Earl of Sandwich from 1729 to 1792. He is known to have had a gambling addiction. It is said that, in 1762, as he sat for hours at the card table, he asked the house cook to bring something he could eat without getting up. The cook placed meat between two pieces of bread and brought it to him. Thus, the sandwich was born—or at least popularised, since it is difficult to imagine that nobody ever tried that before 1762!

The sandwich is one of the most popular meals across the world. The idea is simple: Two pieces of bread to hold together the substance of your meal. The real meal is what lies between the pieces of bread, but without the bread sandwiching the sustenance, the meal loses its structure.

The word “sandwich” has come to be used in various ways. Interpreters of the Bible often use the word to describe a central thought (or thoughts) sandwiched (or bookended) by a particular idea. (The technical term is inclusio.) Second Peter offers a great example of a theological sandwich. Peter opens his letter with reference to “the knowledge of God and of Jesus our Lord” (1:2) and closes with the same thought: “But grow in the grace and knowledge of our Lord and Saviour Jesus Christ” (3:18). The meat of the letter is sandwiched between the bread slices of the knowledge of Jesus Christ.

This sandwich highlights the reality that growing in the knowledge of Jesus Christ is the key to everything else that Peter says in this letter. If we will identify false teaching and therefore avoid the corruption of the false teachers, the key is to grow in the knowledge of Jesus Christ. Zeroing in on false teaching is of limited value. We should instead focus on growing in our knowledge of Christ as the means to identifying error. How, then, do we grow in the knowledge of Jesus Christ as a means to guarding us against the corruption of sin? Here are five considerations.

First, we can only grow in our knowledge of Christ if we have experienced the grace of Christ in the gospel. Paul said that to be saved is to “come to the knowledge of the truth” (1 Timothy 2:4). The first step to growing in the knowledge of Christ is to submit to Christ in repentance and faith.

Second, we can only grow in the knowledge of Christ by a slow and steady diet of feasting on Christ through his word. Jesus himself made this connection in his High Priestly prayer: “I have given them the words that you gave me, and they have received them and have come to know in truth that I came from you; and they have believed that you sent me” (John 17:8). It was by receiving the message that the Father gave him that they came to know him. We will likewise grow in Scripture only as we give ourselves deliberately and intentionally to the message that God has given in the Scriptures.

Third, we can only grow in the knowledge of Christ by intentional reliance on the Spirit, who leads and guides into truth (John 16:13). To grow in the knowledge of Christ, therefore, we must intentionally pray for the Spirit to illumine him to us. We should read, study, memorise, and meditate on Scripture, but this will only be effective for growth as the Spirit illumines truth about Christ to us (1 Corinthians 2:13–14).

Fourth, we can only grow in Christ by developing and maintaining a teachable spirit. God’s old covenant people were “destroyed for lack of knowledge,” not because knowledge was unavailable, but “because you have rejected knowledge.” They had rejected knowledge in that they had “forgotten the law of your God” (Hosea 4:6). We should always assume that we have much to learn and therefore listen and read with the humble attitude that the teacher or writer has something to teach us. If we assume we have nothing to learn, we will stop growing.

Fifth, we can only grow in the knowledge of Christ to the degree that we are committed to obey what we have already learned. Jesus once said, “If anyone’s will is to do God’s will, he will know whether the teaching is from God or whether I am speaking on my own authority” (John 7:17). Notice that knowing is tied to doing. A commitment to faithful obedience is crucial to our growth in the knowledge of Christ.

As you reflect this morning on 2 Peter 1:1–2, examine whether you have submitted to Christ in the gospel. Having done so, commit to daily feasting on Christ, relying on the Spirit with a teachable spirit, and commit to obey God as you ask to grow more in the knowledge of Christ.