What is the syntactic relation of hum and sāhūn in 107:5?

Supplementary Practice 21: Comparative Rhetorical Study of Sūrat Quraysh and al-Māʿūn

• Read hum solely as a separation pronoun with no predicate sāhūn
• Hum is the nominal subject and sāhūn its predicate
• Make sāhūn a past verb and remove the nominal subject
• Make ʿan ṣalātihim the subject and hum an object