וַיַּ֤רְא הָֽאֱלֹהִים֙ אֶֽת־מַ֣עֲשֵׂיהֶ֔ם כִּי־שָׁ֖בוּ מִדַּרְכָּ֣ם הָרָעָ֑ה וַיִּנָּ֣חֶם הָאֱלֹהִ֗ים עַל־הָרָעָ֛ה אֲשֶׁר־דִּבֶּ֥ר לַעֲשׂוֹת־לָהֶ֖ם וְלֹ֥א עָשָֽׂה׃
하나님이 그들의 행한 것 곧 그 악한 길에서 돌이켜 떠난 것을 감찰하시고 뜻을 돌이키사 그들에게 내리리라 말씀하신 재앙을 내리지 아니하시니라
Ibn Ezra
"And God saw" - that they believed in him. And it [the people's belief] is like this [episode] in [Parshat] Yitro: "before God." (Shemot 18:12).
Malbim
God saw what they did: that is, at first when the people of Nineveh repented, they only regretted what they had done, but did not repent with acts that would rectify their past sins through [positive] action. But after the king's order, God saw through all of their acts that they had repented. They repented through [positive] actions by actually returning stolen items and those obtained unfairly, therefore [the verse says] "And God renounced the punishment," and [this is] despite [the fact] that they only repented for the sin of theft, [and] not for idol worship, [even] with [taking] all this [into account], since their decreed punishment had been sealed because of theft and they rectified this,"he did not carry out the evil"- that is, if the evil was prepared to come upon them in [the course of] nature, according to the system [of the universe], then it would come to them then as well, after that [which] they worshiped idols in Eden and were under [the control of the natural] system- God would not strip the nature [of the world with regards to reward and punishment] for idol worshipers! But since the evil was not destined to come them from the side of the nature [of the world], only God set in place for the future to do the evil through the punishment (?), and when they repented for the sin of theft he did not carry out [the evil], and left them to behave according to the nature the system.