Lent Psychosabbath. When what is its significance?
The Saturday before Palm Sunday is called - "Saturday of Souls" or Psycho Saturday. It is the first of the two Psychosabbaths of the year (the second is performed on the Saturday before Pentecost Sunday).
The reason our Church established them, despite the fact that every Saturday is dedicated to those who are asleep (See here), is to be remembered steadily those who do not receive someone alive due to circumstances to have a memorial service for the repose of their Soul on the Day of Judgment.
Because on Apkreos Sunday we commemorate the Second Coming of Christ and our sleeping ones have not yet been judged, we remember them today and, invoking His infinite mercy, we ask God with the memorial service we are doing, to give them rest. At the same time, we also remember death and this urges us to repentance.