Abū Hurayra said, “I heard the Prophet (ﷺ) the truthful confirmed one, Abu’l-Qāsim, say, ‘Mercy is only removed from the one who is destined for wretchedness.” This wretchedness is evil for  in the tradition narrated by ‘Abdullah ibn Mas’ūd, may God be pleased with him, it states,
The evil one is he who is evil in the womb of his mother and the good one is he who takes a lesson from the (fate of) others. The narrator came to a person from amongst the Companions of Allah’s Messenger (ﷺ) who was called Hudhaifa b. Usaid Ghifari and said: How can a person be an evil one without (committing an evil) deed? Thereupon the person said to him: You are surprised at this, whereas I have heard Allah’s Messenger (ﷺ) as saying:
When forty-two nights pass after the semen gets into the womb, Allah sends the angel and gives him shape. Then he creates his sense of hearing, sense of sight, his skin, his flesh, his bones, and then says: My Lord, would he be male or female? And your Lord decides as He desires and the angel then puts down that also and then says: My Lord, what about his age? And your Lord decides as He likes it and the angel puts it down. Then he says: My Lord, what about his livelihood? And then the Lord decides as He likes and the angel writes it down, and then the angel gets out with his scroll of destiny in his hand and nothing is added to it and nothing is subtracted from it. 
The opposite of wretchedness or evil, is happiness or goodness. Whoever God has known in His pre-eternal knowledge to be wretched is in truth wretched, even if they appear to be happy, blessed and good. In truth, the truly wretched one is that person who enters into the Fire, a status that will not be known until the next life. As such, we don’t know our actual status with God until then. This is a sobering reality.
However, there are indications about our status in the next life to be found this world. This tradition, it appears, is one of the instructions from the Prophet ﷺ that gives us insight into the reality of our hearts and position with God. In principal, one cannot give another that which they don’t have themselves. So, if a person does not have goodness, mercy, and the like in their own hearts, they are not able to show toward other people. Thus his words, ﷺ , indicate that if we are not goodly to people it is because we can’t give them something that we ourselves do not have, i.e., mercy. In other words, the reason why we are not pleasant to them is because we don’t have that capacity in us ourselves and those who do not have this capacity are not fit for Paradise. In fact, they are suited for the Fire, the abode of wrath for those who hearts are devoid of mercy.
The tradition also indicates that the heart’s basis is in mercy, as he said, (ﷺ),‘Mercy is only removed from the one who is destined for wretchedness.’ This is to say that we are merciful by nature. Children, and overwhelmingly so, and the younger they are, tend to prove this statement to be true, as they are quite merciful and mercified from birth. In fact, when we encounter children that are not merciful we recognize that there is something amiss in their lives. May Allāh restore our child-like natures. Āmīn!
 Al-Bukhārī, Kitāb Adab al-Mufrad
 Ṣaḥīḥ Muslim