The background and consequences of this case are quite complex.
Tips
history
From 《南齐书·高逸传论》: 今树以前因，报以后果 - 'one plants a prior cause and reaps a later fruit'. The framing draws directly on Buddhist karmic vocabulary, which had entered literary Chinese via translated sutras.
culture
因 and 果 are the foundational Buddhist pair 'cause' and 'fruit (result)'. The idiom is thoroughly secular today, but the grammatical pattern is a gift from the translators of 4th-6th century sutras.
