After the unity of God, the mercy and compassion of God seems to be the most important aspect of the Qur’anic image of Him. There are more attributes in this category than any other category and altogether they are by far the most often repeated characteristics of God in the Qur’an. Every chapter of the Qur’an starts with بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِ except Chapter 9.
However, Chapter 27 contains this phrase twice: once in the beginning and then again in the verse 27:30. In such an extraordinarily important phrase which stands as a symbol for Islam and occurs 114 times in the Qur’an and with which Muslims are highly recommended to begin every act or speech, two attributes in particular are singled out: al-Rahman and al-Rahim.
Another interesting case is the first chapter of the Qur’an, the Opening, which has seven verses. Indeed, this chapter is a brief account of Islam, without which no ritual prayer can be performed. The chapter starts with the phrase بِسْمِ اللهِ الرَّحْمنِ الرَّحِيمِ as usual, but then proceeds as follows:
“All praise belongs to God, Lord of all the worlds, the All-compassionate, the All-merciful, Master of the Day of Retribution. You [alone] do we worship, and to You [alone] do we turn for help. Guide us on the straight path, the path of those whom You have blessed, not the path of those who have incurred Your wrath, nor are astray.” (1:2-7) 
As we see, in this important chapter four attributes of God are mentioned: the Lord of all the worlds, the All-compassionate, the All-merciful and Master of the Day of Retribution. These four must be very significant and therefore they deserve careful study In brief, they refer to two acts of God: the first is that He is the one who runs the universe and the second is that He is the one who establishes justice. 
1. الْحَمْدُ لِلَّـهِ رَبِّ الْعَالَمِينَ ﴿٢﴾ الرَّحْمَـٰنِ الرَّحِيمِ ﴿٣﴾ مَالِكِ يَوْمِ الدِّينِ ﴿٤﴾ إِيَّاكَ نَعْبُدُ وَإِيَّاكَ نَسْتَعِينُ ﴿٥﴾ اهْدِنَا الصِّرَاطَ الْمُسْتَقِيمَ ﴿٦﴾ صِرَاطَ الَّذِينَ أَنْعَمْتَ عَلَيْهِمْ غَيْرِ الْمَغْضُوبِ عَلَيْهِمْ وَلَا الضَّالِّينَ ﴿٧﴾
2. Shomali, Mohammad Ali & Mahnaz Heydarpoor, The image of God in Quran, p. 18-19.