How do the sources of iqtibās and taḍmīn differ?

Comprehensive Review and Application: Bayān, Badīʿ and the Final Rhetorical Arts

• Iqtibās uses Qurʾān/hadith; taḍmīn another poet’s verse
• Both draw only on idioms
• Iqtibās uses one’s own verse; taḍmīn one’s own prose
• Both require reversible letter sequences