פירוש על ברכות 125:7

And it is not to be taken as a general rule; therefore the Mishnah quotes another instance.

I.e. the quotation is not a greeting but the message which the angel was commanded to communicate ; therefore this verse cannot be used to support the teaching that the Divine Name must be mentioned in a salutation.

By "thy mother" is here meant the great men of the past. Follow in their ways ; so that even if Boaz used the Name of his own accord, act likewise.