Consider the signal $\sin(\omega t)$, it has frequency content $\omega$. Delayed by 1 sec. the signal will be same so same frequency content but our time t=0 has already started 1 sec before so waveform will only shift by 1 sec right i.e phase not frequency component.
As one can see from equation $G(w) = e^{-j\omega t}$ will cause only a phase change in a circular fashion so that whatever delay is there wrt T of the original signal.
hope it helps
Aman Deep
General electrical engineer
Bihar, India