Adam repents and supplicates to Allah
Allah tells;
فَتَلَقَّى ادَمُ مِن رَّبِّهِ كَلِمَاتٍ فَتَابَ عَلَيْهِ إِنَّهُ هُوَ التَّوَّابُ الرَّحِيمُ
Then Adam received from his Lord Words. And his Lord pardoned him (accepted his repentance). Verily, He is the One Who forgives (accepts repentance), the Most Merciful.
Mujahid, Sa`id bin Jubayr, Abu Al-Aliyah, Ar-Rabi bin Anas, Al-Hasan, Qatadah, Muhammad bin Ka`b Al-Qurazi, Khalid bin Ma`dan, Ata Al-Khurasani and Abdur-Rahman bin Zayd bin Aslam have stated that the above Ayah is explained by Allah's statement,
قَالَا رَبَّنَا ظَلَمْنَأ أَنفُسَنَا وَإِن لَّمْ تَغْفِرْ لَنَا وَتَرْحَمْنَا لَنَكُونَنَّ مِنَ الْخَـسِرِينَ
They said;"Our Lord! We have wronged ourselves. If You forgive us not, and bestow not upon us Your mercy, we shall certainly be of the losers." (7;23)
As-Suddi said that Ibn Abbas commented on,
فَتَلَقَّى ادَمُ مِن رَّبِّهِ كَلِمَاتٍ
(Then Adam received from his Lord Words),
"Adam said, `O Lord! Did You not created me with Your Own Hands?'
He said, `Yes.'
He said, `And blow life into me?'
He said, `Yes.'
He said, `And when I sneezed, You said, `May Allah grant you His mercy.' Does not Your mercy precede Your anger?'
He was told, `Yes.'
Adam said, `And You destined me to commit this evil act?'
He was told, `Yes.'
He said, `If I repent, will You send me back to Paradise?'
Allah said, `Yes."'
Similar is reported from Al-Awfi, Sa`id bin Jubayr, Sa`id bin Ma`bad, and Ibn Abbas.
Al-Hakim recorded this Hadith in his Mustadrak from Ibn Jubayr, who narrated it from Ibn Abbas.
Al-Hakim said, "Its chain is Sahih and they (Al-Bukhari and Muslim) did not record it."
Allah's statement,
إِنَّهُ هُوَ التَّوَّابُ الرَّحِيمُ
Verily, He is the One Who forgives (accepts repentance), the Most Merciful.
means that Allah forgives whoever regrets his error and returns to Him in repentance.
This meaning is similar to Allah's statements,
أَلَمْ يَعْلَمُواْ أَنَّ اللَّهَ هُوَ يَقْبَلُ التَّوْبَةَ عَنْ عِبَادِهِ
Know they not that Allah accepts repentance from His servants. (9;104)
وَمَن يَعْمَلْ سُوءاً أَوْ يَظْلِمْ نَفْسَهُ
And whoever does evil or wrongs himself. (4;110)
and,
وَمَن تَابَ وَعَمِلَ صَـلِحاً
And whosoever repents and does righteous good deeds. (25;71)
The Ayat mentioned above, testify to the fact that Allah forgives the sins of whoever repents, demonstrating His kindness and mercy towards His creation and servants.
There is no deity worthy of worship except Allah, the Most Forgiving, the Most Merciful