The custom started long, long ago when first the wise men three... gave gifts of love, of love, to a newborn baby.
41 seconds sound clip from the Santa Claus Is Comin' to Town (1970) movie soundboard.
You can hear this line at 00:43:20.857 in the Blu-ray version of the movie.
Quote context
[...]
- And then Kris and Jessica placed their wedding gifts to each other under the trees.
- No church ever looked nicer.
- Oh, please. Let me have just a little magic.
- The very first Christmas trees.
- But there was no rest for our little group of outcasts.
- This is it, people. Ah, yes, this is it.
- And that's just what they did. And in no time at all...
[...]