What prevented the acceptance of their spending was that they rejected God and His messenger, and they do not attend to the contact prayer except lazily, and they do not spend except unwillingly.
Translation endnotes
[9:54] This verse is another piece of evidence that sala prayers were known since Abraham and were practiced by Meccan polytheists (8:35; 21:73). This is another answer for those who reject Quran's assertion that it is complete, perfect, and sufficiently detailed, and then ask, "Where can we find the details of sala prayers in the Quran?" (6:19, 38,114). One can find the details of sala prayer for themselves by just studying the sixty plus verses that mention sala prayer.