In classical fiqh, the term "jihad" refers to armed struggle against unbelievers. Classical jurists developed an elaborate set of rules pertaining to jihad, including prohibitions on harming those who are not engaged in combat. According to Bernard Lewis, "t no time did the classical jurists offer any approval or legitimacy to what we nowadays call terrorism" and the terrorist practice of suicide bombing "has no justification in terms of Islamic theology, law or tradition". In the modern era the notion of jihad has lost its jurisprudential relevance and instead gave rise to an ideological and political discourse. While modernist Islamic scholars have emphasized defensive and non-military aspects of jihad, some radical Islamists have advanced aggressive interpretations that go beyond the classical theory. For al-Qaeda ideologues, in jihad all means are legitimate, including targeting Muslim non-combatants and the mass killing of non-Muslim civilians. According to these interpretations, Islam does not discriminate between military and civilian targets, but rather between Muslims and nonbelievers, whose blood can be legitimately spilled.