Mark 2:21

2:21 No one sews a patch of unshrunk cloth on an old garment; otherwise, the patch pulls away from it, the new from the old, and the tear becomes worse.

Mark 9:18

9:18 Whenever it seizes him, it throws him down, and he foams at the mouth, grinds his teeth, and becomes rigid. I asked your disciples to cast it out, but ¹  they were not able to do so.” ² 

---

¹ tn Here καί (kai) has been translated as “but” to indicate the contrast present in this context.

² tn The words “to do so” are not in the Greek text, but have been supplied for clarity and stylistic reasons.