οὕτως γὰρ ἠγάπησεν ὁ θεὸς τὸν κόσμον, ὥστε τὸν υἱὸν τὸν μονογενῆ ἔδωκεν, ἵνα πᾶς ὁ πιστεύων εἰς αὐτὸν μὴ ἀπόληται ἀλλ᾿ ἔχῃ ζωὴν αἰώνιον.

What John 3:16 literally means in Greek:

“For God so loved the world, so that He gave His only and unique Son, that all the [one] believing in Him should not perish [by themselves], but have eternal life.”

This is not exactly the same as “whoever believes in Him should not perish…” Isn’t it?