Christian: Symbols of Easter, of Jesus’ resurrection.
ACIM: Symbols of forgiveness, for in the Course’s teaching, the recognition of innocence is what leads to resurrection, and forgiveness is the recognition of innocence. Thus, the Course calls lilies “the white and holy sign the Son of God is innocent” (T-20.I.2:1). When you forgive your brother you are giving him lilies rather than thorns (which symbolize the crucifixion that comes from guilt), placing them on his inner altar and thereby placing them on your own as well. See T-20.I-II.