غَافِرِ الذَّنبِ وَقَابِلِ التَّوْبِ

The Forgiver of sin, the Acceptor of repentance,

means, He forgives sins that have been committed in the past, and He accepts repentance for sins that may be committed in the future, from the one who repents and submits to Him.

شَدِيدِ الْعِقَابِ

the Severe in punishment,
means, to the one who persists in transgression and prefers the life of this world, who stubbornly turns away from the commands of Allah and commits sin.
This is like the Ayah:
نَبِّىءْ عِبَادِى أَنِّى أَنَا الْغَفُورُ الرَّحِيمُ
وَأَنَّ عَذَابِى هُوَ الْعَذَابُ الاٌّلِيمُ
Declare unto My servants that truly I am the Oft-Forgiving, the Most-Merciful. And that My torment is indeed the most painful. (15:49-50)
These two attributes (mercy and punishment) are often mentioned together in the Qur'an so that people will remain in a state of both hope and fear.
ذِي الطَّوْلِ
the Bestower.
Ibn Abbas, may Allah be pleased with him, said,
'This means He is Generous and Rich (Independent of means).'
The meaning is that He is Most Generous to His servants, granting ongoing blessings for which they can never sufficiently thank Him.
وَإِن تَعُدُّواْ نِعْمَةَ اللَّهِ لَا تُحْصُوهَا
And if you would count the favors of Allah, never could you be able to count them... (16:18)
لَاا إِلَهَ إِلاَّ هُوَ
La ilaha illa Huwa,
means, none is equal to Him in all His attributes; there is no God or Lord besides Him.
إِلَيْهِ الْمَصِيرُ
to Him is the final return.

means, all things will come back to Him and He will reward or punish each person according to his deeds.

وَهُوَ سَرِيعُ الْحِسَابِ

and He is Swift at reckoning. (13:41)

Renungan tentang Surah Ghafir Ayah 1