What does John 14:10 mean?

These two verses echo remarks Jesus once made to His critics (John 5:30–40). There, Jesus pointed to human testimony, evidence of miracles, and the written Scripture as proof that His claims were true. In response to Philip's confusion about "seeing" God (John 14:8), Jesus remarked that to see Him is to see God. He now expands on that idea by listing reasons why others should accept the idea that Jesus is God (John 10:30).

First is the idea of God being "in" Jesus. In this context, the meaning is that of character—in other words, Jesus acts perfectly according to the will of God (John 8:18; Hebrews 1:3). Nothing Jesus says or does contradicts the idea that He is God (John 8:46; Hebrews 4:15), and His actions confirm that He is acting according to the Father's will (John 9:4). For the disciples, this ought to be an obvious point, which is why Jesus again poses a rhetorical question.

The second point Jesus makes is that of His words: what He says are the statements of God (John 7:16; 12:49–50). As with His actions, Jesus' speech only further supports that what He says is true (Mark 1:22).

The third piece of evidence are the "works" of God, by which Jesus partly means miracles (John 5:36). That idea will be expanded in the next verse. This reference to "works" also connects to the idea of other, more mundane actions. Supernatural or natural, everything Jesus does is consistent with the nature of God.

Another concept expanded in verse 11 is the scope of who ought to "believe" in Christ. In this verse, Jesus' question "Do you not believe" here is the Greek singular. His references to "believe" in the following verse are in the Greek plural, implying "you all" ought to believe.