But they hamstrung her and so became regretful. (26:157)

Almuntakhab Fi Tafsir Alquran Alkarim

Nevertheless they defiantly disabled her by cutting her hamstring muscles. (Their outrage on consecrated objects invited their ruin) which led to pining regrets and vain repentances

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(26:157) Yet they hamstrung her, *105 and then became regretful,

But they hamstrung her and so became regretful. meaning

*105) This dces not mean that as soon as they heard the challenge, they attacked the she-camel at once and hamstrung her. Actually, when the she-camel became a problem for the whole nation, the hearts of the people were filled with rage, and they began to hold lengthy consultations as to how to get rid of her. At last, a haughty chief undertook the task of putting an end to her, as mentioned in SurahAsh-Shams thus: "When arose the most villainous of the people.. ." (v. 12) and in Surah Al-Qamarthus: "They appealed to their companion; so he took up the responsibility and hamstrung (her)." (v. 29).
 

But they hamstrung her and so became regretful. meaning in Urdu

مگر انہوں نے اس کی کوچیں کاٹ دیں اور آخرکار پچھتاتے رہ گئے