What does John 12:25 mean?

In other passages, Jesus speaks of the fundamental choice between the world and God (Matthew 10:39; Mark 8:35–36). A person cannot cling to worldly things and still make God their top priority. In prior verses, Jesus used the analogy of a seed: it must "die" in order to fulfill its purpose. The symbolism is that of a seed being planted, then growing to maturity. Those who seek to truly follow Christ have to—as it would seem to the world—lose everything. The end result, however, is exactly what the seed—the believer—was always intended for, which is something greater and more glorious (1 Corinthians 15:36–42).

It's important to understand the narrow context of Jesus' words here. The point is not that only those who live in deliberate poverty will be saved. Nor is it that a person must perform the right kind of actions in order to be with God in eternity. Rather, this is a reference to a person's state of mind. This is why Jesus uses the dichotomy of "love" and "hate," with respect to one's earthly life. Just as Jesus was not commanding people to objectively "hate" their family (Luke 14:26), He is not telling us to objectively "hate" our lives. Rather, He's saying that we ought to put 100% of our priority, emphasis, and effort into the will of God. Those who want to cling to the world, instead of Christ, demonstrate that they "love" the world too much to sincerely follow Him (Mark 10:21–23).