Al-Isra · Al-Kahf

Both end with giving glad tidings to the believers but 17:9 uses 'yubashiru' (indicative) while 18:2 uses 'yubashira' (subjunctive) — a single vowel difference in the verb form.

Yunus · Al-Kahf

Both use the same parable: 'the example of worldly life is like rain We send down from the sky; the vegetation of the earth mingles with it then it withers'; 10:24 develops the metaphor fully, 18:45 gives a compressed version.

Al-Kahf · Al-Insan

18:29 'fa man sha'a fa l-yu'min wa man sha'a fa l-yakfur' and 76:3 'inna hadaynahu al-sabil imma shakiran wa imma kafura' both state that guidance is given and humans choose — one in a threat context, the other in a declaration of human freedom.

Al-Kahf · Al-Kahf

Khidr's repeated reproach to Musa — 18:72 says 'alam aqul innaka lan tastati'a' while 18:75 adds 'laka' after 'aqul', a single word difference tested in tajwid revision.

Al-Kahf · Fussilat

Verbatim opening: 'say: I am only a man like you, to whom it has been revealed that your God is one God'; 18:110 closes Al-Kahf, 41:6 opens a passage in Fussilat -- both assert the Prophet's humanity alongside strict monotheism.