سَكَنَ الْبَحْرُ وَهَدَأَتِ الرِّيحُ.
The sea grew calm, and the wind subsided.
Both assertions describe tranquility within one scene, giving their coordination a plausible semantic link. Unrelated statements should not be joined merely because both use the past tense or the same morphological pattern.
The claimed jāmiʿ must be defensible in meaning and context. Grammatical similarity may support a reading, but it cannot by itself establish a rhetorical relationship.