This is how Meher Baba describes karma (in Vladimir Stojakovic’s book):
The Sanskaras (impressions or accumulated imprints of past experience) deposited by speciﬁc actions and experiences render the mind susceptible to similar actions and experiences; but after a certain point is reached, this tendency is checked and counteracted by a natural reaction consisting of a complete change over to its direct opposite, making room for the operation of opposite sanskaras.
A person soon realizes the incompleteness of the experience of one opposite, and unconsciously seeks to restore the lost balance by going over to the other opposite. Thus the person who has had the experience of killing will develop a psychological need for and susceptibility to getting killed.
In killing another person he has appreciated only one portion of the total situation in which he is a party, namely, the part of killing. The other complementary half of the total situation, namely, the role of being killed, remains for him an unknown, which, nevertheless, has introduced itself in his experience.
Thus there arises the need to complete the experience by attracting on oneself the opposite of what one has personally undergone, and consciousness has a tendency to fulﬁll this new and pressing need. The person who has killed another will soon develop a tendency to get himself killed in order to encompass the entire situation with personal experience.
Like the shuttle of a weaver’s loom, the human mind moves within two extremes, developing the warp and the woof of the cloth of life. To use a geometrical metaphor, the development of our psychic life is best represented not as a straight line but as a zigzag course.
The amount of oscillation becomes less and less as the individual approaches the goal, and it completely subsides when he realizes it.