What follows is my provisional translation (in other words, not official or authorized; see here for more) of a passage from a Tablet of ʻAbduʼl-Bahá, the original text of which is published in Máʼidiy-i-Ásmání, vol. 2, p. 106.
As to goodly deeds and charitable donations, these will certainly diminish the misdeeds of the departed and add to their good works, for others will benefit from those generous acts. It would be as if the deceased had sought forgiveness for themselves, and as the benefit thereof is obvious, it is better and more important to perform goodly deeds and make charitable donations.*
* One personal interpretation: ʻAbdu’l-Bahá seems to be saying that it is better to donate money in the name of the deceased because, in so doing, you are improving their state in the afterlife and helping people in this world with your donation in the process, whereas the potential benefits of seeking forgiveness in this world are confined only to the suppliant.
A typescript of the original Persian text of this passage appears below.