For God so loved the world,
that he gave his only begotten Son,
that whosoever believeth in him should not perish,
but have everlasting life.
John 3:16
PROBATION for mankind: ....he gave his only begotten Son,... God DID NOT ask mankind for permission to give us a period of probationary grace on this earth.
JUSTIFICATION involves your ACCEPTANCE of His offer: ....that whosoever believeth in him... (you can't earn it--but YOU have to accept it)