Mercy is obtained by those capable of donating it. Works of Jubilee indulgence

Mercy towards our brothers and sisters is concretized via a set of corporal or spiritual works that the tradition has passed down to us.
When were they established? In all likelihood the Middle Ages ushered in the enumeration of a specific list of seven works of mercy, that we describe as corporal – six from the Gospel of Matthew (ch. 25) plus the burial of the dead, found in the book of Tobias – accompanied by a list of seven spiritual works of mercy. Indeed, the appeal exerted by the number seven and by the septenaries on the soul of medieval men is known. In fact, in that epoch was celebrated the triumph of seven, symbol of order and completeness, representing unity and multiplicity.
And thus charity towards others took the shape of the works of corporal mercy – to feed the hungry; to give drink to the thirsty; to clothe the naked; to harbour the harbourless; to visit the sick; to ransom the captive; to bury the dead – and of spiritual works: to instruct the ignorant; to counsel the doubtful; to admonish sinners; to bear wrongs patiently; to forgive offences willingly; to comfort the afflicted; to pray to God for the living and the dead. The list is open to updates according to different needs.
However, the fact that the list was fixed during the Medieval period doesn’t mean that in the previous centuries works of mercy were unknown. The Fathers of the Church, in teaching others the need to help the poor, on various occasions ascribed a spiritual connotation to the works of mercy. Thus proclaiming the World of God was considered equal to feeding the hungry.

Is it more important to help the poor in material needs or to give advice to a person in doubt?

The question was raised also by Medieval scholars. In fact, Saint Thomas Aquinas (1225 – 1274) established the primacy of the spiritual works of mercy. He called them “spiritual alms” because they alleviate the spirit. And since the spirit is superior in dignity compared to the body, spiritual alms are necessary. Indeed, St. Thomas explained that the spiritual good donated with spiritual almsgiving has a higher value than that given with corporal works.
Yet, in practice things seem different:

Not only material needs appear to be the most urgent, they actually become the only ones that are considered.

Moreover, some seem not to be in need of spiritual support. But this should not lead us to overlook them, since while the needs of the body can be urgent, spiritual alms help individual growth. This epitomizes the Christian understanding of the human person, which is not only a “material problem” but rather a spiritual being, called to interior fulfillment, even with scarce material goods.
The importance ascribed by the Holy Father to the fulfillment of the fourteen works of mercy to the extent of attaching the gift of Jubilee indulgence even to one of them only, is known. There is great coherence in this. Those who perform merciful acts towards others are in the most authentic condition to receive the mercy of the Father. Merciful God – we are taught by Saint John Damascene (676 – 749) rejoices when he sees his children hasten to help others. Merciful God wants us all to perform acts of mutual goodness during our life and after our death.