When is the “last day” that is referred to in the book of John?
The Rapture? The Second Coming? A series of “last days’?

John 6:39
And this is the will of him who sent me, that I shall lose none of all those he has given me, but raise them up at the last day

John 6:40
For my Father’s will is that everyone who looks to the Son and believes in him shall have eternal life, and I will raise them up at the last day.

John 6:44
“No one can come to me unless the Father who sent me draws them, and I will raise them up at the last day

John 6:54
Whoever eats my flesh and drinks my blood has eternal life, and I will raise them up at the last day.