What Are the Hardest Questions of Christianity? A Cross-Faith Comparison

Judaism doesn't frame its hardest questions around a single figure like Jesus, but it does grapple seriously with theodicy — the justice of God in the face of suffering — and with the limits of human legal reasoning. Deuteronomy 17:8 acknowledges that some cases in law become genuinely intractable, requiring escalation to a higher authority: when a matter is "too hard" for local judges, the community must seek divine guidance Deuteronomy 17:8. This built-in humility about human reasoning is a cornerstone of rabbinic thought.

The question of whether anything is truly impossible for God is answered emphatically in Genesis 18:14, where God asks rhetorically, "Is any thing too hard for the LORD?" Genesis 18:14. Yet Jewish theology, especially after the Holocaust, has wrestled painfully with how that omnipotence squares with historical catastrophe. Scholars like Eliezer Berkovits (1973) and Emil Fackenheim debated whether traditional theodicy could survive Auschwitz. The tension between God's power and human suffering remains Judaism's most existentially urgent hard question.

Additionally, Jeremiah 23:33 captures a different kind of hard question — the burden of prophetic speech itself, and whether humans can reliably claim to carry God's word Jeremiah 23:33. The question of authentic prophecy versus false prophecy has never been fully resolved in Jewish tradition, and it bleeds into questions about the canon, authority, and interpretation that still divide Orthodox, Conservative, and Reform communities today.

Christianity's hardest questions cluster around a handful of irreducible tensions. The first is the problem of evil: if God is omnipotent and good, why does suffering exist? This isn't unique to Christianity, but it's sharpened by the doctrine of the Incarnation — if God himself entered human suffering in Christ, what does that mean for those who still suffer? Paul confronts the stakes bluntly in 1 Corinthians 15:19: "If in this life only we have hope in Christ, we are of all men most miserable" 1 Corinthians 15:19. The resurrection, then, isn't optional theology — it's the load-bearing wall of the entire Christian worldview.

A second cluster of hard questions involves predestination, free will, and salvation. Can a person genuinely choose faith, or is that choice itself a gift? 2 Corinthians 13:5 urges believers to "examine yourselves, whether ye be in the faith" 2 Corinthians 13:5, implying that assurance of salvation is not automatic — a verse that fueled centuries of Reformation debate between Luther, Calvin, and Arminius. The question of who is saved, and on what basis, remains one of the most divisive in Christian history.

A third hard question is the nature of Jesus himself — fully human and fully divine simultaneously. Mark 10:5 records Jesus attributing a Mosaic concession to "the hardness of your heart" Mark 10:5, which implies Jesus had authority to reinterpret Torah. That claim to authority is precisely what makes the Christological question so sharp: was he a prophet, a moral teacher, or God incarnate? The Council of Nicaea (325 CE) attempted a definitive answer, but theologians like Arius, Nestorius, and in the modern era John Hick have kept the debate alive.

Finally, the question of eternal damnation is arguably Christianity's most emotionally difficult hard question. Mark 10:24 records Jesus warning that trusting in riches makes entering God's kingdom extraordinarily difficult Mark 10:24, and by extension, many passages suggest that most people may not enter at all. Universalism, annihilationism, and traditional eternal conscious torment represent three competing answers that no ecumenical council has fully settled.

Islam approaches hard theological questions from a starting point of radical divine unity (tawhid) and omnipotence. The rhetorical question in Jeremiah 32:27 — "Is there any thing too hard for me?" — resonates deeply with Islamic theology, which insists that Allah's power is absolute and unconditioned Jeremiah 32:27. From this foundation, Islam's hardest questions tend to be about the relationship between divine decree (qadar) and human moral responsibility: if God wills all things, how can humans be held accountable for sin? This debate between the Mu'tazilites and Ash'arites in the 9th–10th centuries CE was Islam's version of the predestination controversy.

Islam's hardest questions about Christianity specifically concern the Trinity and the crucifixion. The Quran (Surah 4:157) denies that Jesus was crucified in the way Christians claim, and Surah 5:73 rejects the Trinity as a form of shirk (associating partners with God). These aren't peripheral disagreements — they strike at the heart of what Christianity considers its most essential doctrines. Islamic scholars like Ibn Taymiyya (1263–1328) and, more recently, Ahmed Deedat, have argued that Christianity's hardest questions are actually self-generated contradictions that Islam resolves by returning to strict monotheism.

The question of suffering and endurance also appears in Islamic thought, though framed differently than in Christianity. The call to "endure hardness" as a soldier of faith 2 Timothy 2:3 — a phrase from 2 Timothy — finds a parallel in the Islamic concept of sabr (patient perseverance), which is considered a cardinal virtue. But Islam doesn't frame this endurance around the redemptive suffering of a divine figure; it's a human discipline in submission to God's will. That distinction is, arguably, the deepest fault line between the two faiths.