It is a song of salvation, redemption, resurrection, and comfort.
The reference is double: The grieving Mary on Easter morning and meeting the resurrected Christ whom she mistakes for the gardener....
Also, Mary Magdeline, the prostitute, who wept in repentance and washed the feet of Christ with her tears.
The message is: Don't dispare....Our GOD is a GOD of miracles and awsome power.....He is the same GOD ....both "old" and "new." As he did in the past...he can do today.