What does John 14:21 mean?
Earlier in this passage, Jesus noted that those who love Him would obey His teachings (John 14:15). He followed that statement with reassurance that the Holy Spirit would come to be in believers (John 14:17). Our ability to follow the will of God depends on the influence of His Spirit (1 Corinthians 2:14–16). Later, Jesus will reinforce this idea of the Spirit guiding and teaching believers (John 15:26; 16:7–11).Here, a person's obedience to Christ's teaching is presented as evidence that they do, indeed, have faith in Him. Good works cannot produce salvation (Titus 3:5), but salvation will produce an attitude of obedience (Romans 1:5). Passages such as James 2:18 echo this same sentiment. John, himself, makes note of this idea many times in his letters (1 John 2:3–6; 2 John 1:6; 3 John 1:11). At no point does Scripture suggest that we must do good to earn or keep our salvation. Yet, it frequently indicates that salvation influences our lives—where there is no such influence, there is no faith.
This idea of being "manifest" to the world follows from Jesus' earlier comment about the world not seeing or accepting the Holy Spirit (John 14:17). Those who reject God won't see Him—those who reject Christ reject God (John 14:9). Those who truly love God are those who accept Him, in faith, and receive the Holy Spirit (John 14:15–17). In a very literal sense, the world will no longer see Jesus—the crucifixion represents the end of His physical appearance to non-believers (John 14:19). In a spiritual sense, only those who accept Christ will see and understand God (1 Corinthians 2:14).
The "manifestation," so far as it applies to Christians, has a spectrum. For example, those who exhibit greater or more mature love for God will more readily understand Him (John 14:28).
John 14:15–31 contains a prediction about the Holy Spirit. Jesus refers to this as the Spirit of Truth, and promises that the Spirit will arrive to help the disciples carry on after Jesus is ascended to heaven. Throughout this section, a person's love for Christ, their obedience to His teachings, and the indwelling of the Spirit are intertwined. As in prior statements, Jesus is focused on comfort and encouragement. He will continue to highlight the need to maintain faith, based on all He has said and done so far. Later, after advance warnings about what Christians will face, Jesus will return to describing the work and purpose of the Holy Spirit under the new covenant.
Christ reassures His followers that faith in Him is faith in God. To know Christ is to know ''the way, and the truth, and the life'' (John 14:6). The words, actions, and miracles of Jesus should give Christians confidence to trust that He will make good on His promises. Among those are His guarantee that He is preparing to come for us, so we can be where He is. Jesus also predicts the indwelling of the Holy Spirit. This is only available to believers, and this Helper acts to guide, teach, and remind us. Both for the disciples, and for future Christians, these words are meant to be comforting during hard times. Since Christ knew, in advance, what would happen, we can be even more confident to trust Him.
