Praise be to Allaah.
Allaah is the Most Merciful, Most Compassionate, and He is the most Merciful of those who show mercy. His Mercy encompasses all things. Allaah says (interpretation of the meaning):
“and My Mercy embraces all things” [al-A’raaf 7:156]
In Saheeh Muslim it is narrated from Abu Hurayrah that the Prophet (peace and blessings of Allaah be upon him) said:
“Allaah has one hundred parts of mercy, of which He sent down one between the jinn, mankind, the animals and the insects, by means of which they are compassionate and merciful to one another, and by means of which wild animals are kind to their offspring. And Allaah has kept back ninety-nine parts of mercy with which to be merciful to His slaves of the Day of Resurrection.” – Muslim, al-Tawbah, 6908.
It was narrated that ‘Umar ibn al-Khattaab said:
“Some prisoners were brought to the Messenger of Allaah (peace and blessings of Allaah be upon him), and there was a woman among the prisoners who was searching (for her child). When she found her child she embraced him and put him to her breast. The Messenger of Allaah (peace and blessings of Allaah be upon him) said to us, ‘Do you think that this woman would throw her child in the fire?’ We said, ‘No, by Allaah, not if she is able not to.’ The Messenger of Allaah (peace and blessings of Allaah be upon him) said, ‘Allaah is more merciful to His slaves than this woman is to her child.’” – Agreed upon. Al-Bukhaari, 5653; Muslim, 6912.
One aspect of the mercy of Allaah to His slaves is that He sent the Messengers and revealed the Books and laws to organize their lives according to the ways of wisdom, far removed from hardship and difficulty. Allaah says (interpretation of the meaning):
“And We have sent you (O Muhammad) not but as a mercy for the ‘Aalameen (mankind, jinn and all that exists)” [al-Anbiya’ 21:107]
The mercy of Allaah is what will admit His believing slaves to Paradise on the Day of Resurrection. No one will ever enter Paradise because of his deeds alone, as the Prophet (peace and blessings of Allaah be upon him) said: “No one’s deeds will ever admit him to Paradise.” They said, “Not even you, O Messenger of Allaah?” He said, “No, not even me, unless Allaah shower me with His Mercy. So try to be near to perfection. And no one should wish for death; he is either doing good so he will do more of that, or he is doing wrong so he may repent.” Narrated by al-Bukhaari, 5349; Muslim, 7042
So the believer must remain in a state between hoping for the mercy of Allaah and fearing His punishment, for Allaah says (interpretation of the meaning):
“Declare (O Muhammad) unto My slaves, that truly, I am the Oft-Forgiving, the Most-Merciful. And that My Torment is indeed the most painful torment” [al-Hijr 15:49-50]
O Allaah, have mercy upon us, O Most merciful of those who show mercy.
Source: Islam Q&A