Allah the Almighty has said, 'My servant continues to draw near to Me with supererogatory works so that I shall love him.' [Reported by Al-Bukhari]
On the authority of Abu Huraira who said: The Messenger of Allah (peace and blessings of Allah be upon him) said, “Allah the Almighty has said, ‘My servant continues to draw near to Me with supererogatory works so that I shall love him.’” [Reported by Al-Bukhari]
«وما يزال عبدي يتقرب إلي بالنوافل حتى أحبه» رواه البخاري
Allah, the Creator and Fashioner of humans, has obligated certain deeds. Those are deeds that are needed by all humans for the purification of their souls. Beyond those deeds, though, Allah has left the door wide open for individuals to concentrate on those deeds that they are most inclined to. For example, some people are dedicated to their voluntary prayers. Other may be attracted to fasting, charity or the pilgrimage.
There are others who are more inclined to doing good toward others. They perform the obligatory deeds and then beyond that they spend their time tending to others' needs. When these people tend to those matters, they become the key by which they come closer to Allah and enter Paradise.
This reality is all by the mercy of Allah. Beyond the obligatory deeds, people are free to pursue those good voluntary deeds that they are most attracted to. There are so many areas of voluntary deeds that it seems inconceivable that a person could not find some voluntary deed or deeds that she would like to perform in order to get closer to Allah. Allah's path to paradise is wide enough to accommodate all of those different leanings. However, this is all dependent on the individual first fulfilling, in general, the obligatory deeds.
"Commentary on the Forty Hadith of al-Nawawi" - Jamaal al-Din M. Zarabozo, pp. 1408-1409