פירוש על רות 1:15

See, your sister-in-law has gone back. In this [word], the accent is at the beginning [on the first syllable] under the shin, because it is in the past tense. [But,] “and in the morning she would return,”²²Megillas Esther 2:14. the accent is at the end [on the last syllable], on the bais, because it is in the present tense, and so it is in all similar cases.²³See Rashi in Bereishis 29:6.