Does the parable of the rich fool speak to Christians today who save large amounts in retirement accounts so they can live off the interest without touching the principal?

You are correct to note that there are observable similarities between the behavior of the rich fool (Luke 12:13-21) and many who dedicate great energy to amass large retirement portfolios. There are also, however, key differences that need to be considered.

ATTITUDE PREEMPTS AMOUNTS

Allowing Scripture to explain Scripture, we learn that having large amounts of money, whether for retirement or for other purposes, is not sinful. Abraham, Isaac, Jacob, Boaz, David, Zacchaeus, Joseph of Arimathea, and Lydia of Philippi were significantly wealthy people whose relationship with the Lord endured.

Looking more closely at how Jesus concluded his lesson in Luke 12:21, we also learn the key fault of the rich fool: He stored up wealth "for himself" but was "not rich toward God." He was a spiritual and charitable pauper. He forfeited his soul not merely by having money but by being cheerfully content to "take life easy" while alienated from God and indifferent toward the needs of others.

INVITATION FOR SELF-APPRAISAL

So while we dare not apply this parable to all who faithfully or passionately build retirement portfolios, your question remains a valuable one that calls all of us to honest self-evaluation regarding crucial questions about wealth. How much is reasonably enough for my long-range purposes? What am I to do with wealth should the Lord give it to me? The apostle Paul addresses pertinent issues of attitudes and purposes in 1 Timothy 6:6-10, 17-19. Ponder these words!

Admittedly, the answer to "How much is enough?" may vary from person to person. The Bible does not provide specific amounts or formulas to allow us to calculate what is proper or improper. But too often greed and lack of confidence in divine providence coupled with a disregard for benevolent giving exert too much influence on zealous savers. Our American culture seldom reflects the old adage attributed to John Wesley: "Make all you can, save all you can, give all you can." The first two without the third are spiritually and ethically unhealthy. It may be hard to defend the strategy, as you phrased it, to "live off the interest without touching the principal" if a concern for the gospel work and the needs of others are not included in the strategy. Having money in the bank or in retirement funds and being a cheerful and generous giver (2 Corinthians 9:6,7) display a healthy attitude toward God’s gifts.

TO ILLUSTRATE