Midrash for Makkot 39:4

אי הכי מאי למימרא הכא במאי עסקינן כגון דעיילינהו בטיבלייהו וקסבר מתנות שלא הורמו כמי שהורמו דמיין

If so then what would be the need to say it? [It should have been obvious.] Here we are dealing with a case where he brought it into [Jerusalem] in an untithed state, and he is of the opinion that gifts that weren't yet given are considered as if they were given.

Sifrei Devarim