Wiktionary
n. (context idiomatic English) an inevitable result; something that is bound to happen
Wikipedia
Matter of Time is the first studio album by the band Axium. The album was mixed, mastered, and produced by Mitch Rosenow and features David Cook (vocals, guitar); Bobby Kerr (drums); Jerron Nichols (bass); and Jeff Shrout (guitar).
Usage examples of "matter of time".
Fairchild was showing no signs of tiring, and it was only a matter of time—.
Given this indisputable fact, it can only be a matter of time before another and far larger impact wipes us out too.
If a complete unified theory was discovered, it would only be a matter of time before it was digested and simplified in the same way and taught in schools, at least in outline.
All over the city people are dying, but in this one place there is a ball and the people there are dancing and drinking and pretending nothing is amiss-although it is only a matter of time before the plague will come to them and they, too, will die.
And it would only be a matter of time before exploration on the part of the northern settlement—.
Maybe I'm still softer than I should be, but that's a matter of time.