Be a good thing (that)... phrase
If you say it's a good thing that, you mean it's lucky that.
It was a good thing that it stopped raining; otherwise, I would be soaking wet.
It was a good thing that she was hospitalized immediately after the car crash; therefore, she is still alive.
It was a good thing that I caught the bus in the nick of time.
Nothing but fortunate chance
If a person has the devil's own luck, he or she has extremely good luck.
If someone is going through a purple patch, that means they have a very successful or lucky period, especially in sports.
Well off or in luck.
The verb "be" must be conjugated according to its tense.
The origin of this idiom is not clear.