Final case is used for marking final cause ("for a house").
Semitic languages had that case, but all of them lost it[1][2][failed verification]. In
Arabic, nouns in such position are marked by the accusative marking (e.g. ǧadda ṭalaban li-l-ʼaǧri he worked hard for the sake of reward).
^Egon K. Keck, Frede Løkkegaard, Svend Søndergaard, Ellen Wulff, Living Waters: Scandinavian orientalistic studies presented to Frede Løkkegaard on his seventy, Page 160,
Google book search, 1990
^Karin C Ryding, A Reference Grammar of Modern Standard Arabic, Page 166,
Google book search, 2005