Someone told me not to say, "I have same thing." They said I have to say "the same thing." Does "the" always have to come before "same" in every sentence?
It would be too much of a generalisation to say that we must always use 'the same' and not 'same', as that defeats the purpose of the article - which is to inform the reader about the state of the noun.
I have the same thing
The article is required here, because it tells us that we know what 'same thing' is: the one we are presumably discussing, not any others. Second language learners often struggle to understand the global reach of 'the', but it is similar to how we would use 'my'.
Same time, same place?
Here we do not use the article, as it is a stock phrase we have shaved down to the essentials because its meaning is specific and we want it to be easy to say at the end of a conversation.
This very same dog ate my lunch yesterday.
Because language has to describe very different things.