Surah At-Taubah, Ayat 73-74

Ayat 73. O Prophet (Muhammad  [SAWW](PBUH)! Strive hard against the disbelievers and the hypocrites, and be harsh against them, their abode is Hell, - and worst indeed is that destination.
Ayat 74. They swear by Allah that they said nothing (bad), but really they said the word of disbelief, and they disbelieved after accepting Islam, and they resolved that (plot to murder Prophet Muhammad  [SAWW](PBUH) which they were unable to carry out, and they could not find any cause to do so except that Allah and His Messenger had enriched them of His Bounty. If then they repent, it will be better for them, but if they turn away, Allah will punish them with a painful torment in this worldly life and in the Hereafter. And there is none for them on earth as a Walî (supporter, protector) or a helper.

Hazrat Anas bin Malik Al-Ansari (MayAllah be pleased with him) the servant of the Messenger of Allah narrated: Messenger of Allah  [SAWW](PBUH) said, "Verily, Allah is more delighted with the repentance of His slave than a person who lost his camel in a desert land and then finds it (unexpectedly)". [Al-Bukhari Hadith # 6309 and Muslim Hadith # 6618].
In another version of Muslim, he said: "Verily, Allah is more pleased with the repentance of His slave than a person who has his camel in a waterless desert carrying his provision of food and drink and it is lost. He, having lost all hopes (to get that back), lies down in shade and is disappointed about his camel; when all of a sudden he finds that camel standing before him. He takes hold of its reins and then out of boundless joy blurts out: 'O Allah, You are my slave and I am Your Rubb'.He commits this mistake out of extreme joy".

Lesson : as mentioned above in Surah At-Taubah Ayat 74. "If then they repent, it will be better for them, but if they turn away, Allah will punish them with a painful torment in this worldly life and in the Hereafter". 1. This Hadith also deals with the inducement and merit of repentance and pardon for sins. Allah is highly pleased with repentance. (2). One will not have to account for a mistake made without any purpose and intention. (3). It is permissible to take an oath to stress on one's pardon. (4). One can quote an instance for the purpose of understanding and elaboration.