In putting acacia at the Master’s temporary grave, Freemasonry follows beliefs which go back to the captivity of the Jews in Egypt.  Here acacia was supposed to have grown about and protected the chest into which Osiris had been tricked by his jealous brother, Typhon.  Searching for her husband, Osiris, Isis discovered the tree in the home of a Phoenician king; for service she rendered the king, he gave her the tree and thus the body of her husband.

Like the evergreens of this country, acacia is hardy.  Sprouts come often from beams and columns made of acacia, the shittah wood of the Old Testament.  The Jews planted it on graves as a symbol of life, and to mark the resting place of the dead that footsteps profane it not.

As myrtle was to the Greeks, mistletoe to the Scandinavians and lotus to the Egyptians, symbols of immortality, so is acacia to Freemasonry.

One Hundred One Questions About Freemasonry, MSA, 2013