What should believers rely on instead of Christ's earthly ministry?

Believers should rely on Christ’s death, burial, and resurrection instead of His earthly ministry. No longer hanging on the earthly ministry means hanging everything on His death, burial, and resurrection. Being in Christ and becoming a new creation rests on that work, not on the earlier earthly ministry.

Les explains that believers are no longer to hang on Christ’s earthly ministry, but are to hang everything on His death, burial, and resurrection. He notes that even though all the sins of the world have been paid for, salvation remains conditional: if anyone is in Christ, he is a new creation. In the Greek, creation and creature are the same word, but creation fits English better because the believer is not merely made a new creature but is a whole new creation of God. That new creative work of the Holy Spirit is what makes a believer a believer; unless it is experienced, one is not a believer. Les then points to 1 Corinthians 12:13, where by one Spirit all believers—not just the best, most spiritual, or those with a particular experience—are baptized into one body.

2 Corinthians 5:16

Wherefore henceforth know we no man after the flesh: yea, though we have known Christ after the flesh, yet now henceforth know we him no more.

Why do believers no longer focus on Christ's earthly ministry?

Believers no longer center on Christ's earthly ministry because their salvation rests entirely on His death, burial, and resurrection. That finished work, applied by the Holy Spirit, makes every believer a new creation and baptizes them into one body, so faith hangs on the gospel accomplished for them rather than on His earthly ministry.