The ambiguity of the “of” in the phrase “the gift of time” is confusing but ultimately helpful. There ARE two interpretations, and each has its truth.
Time presupposes its other as eternity. This is dialectical logic and is supported by usage. So we can say that time is the gift of eternity. “The gift of time.”
The second interpretation is also valid: all things happen in time. “The gifts of time.” This is a matter of contention, perhaps; idealists protest but the logic holds in usage. The space we live and move in is temporal; we are temporal. Every thing is the gift of time.