‘ And, behold, Boaz came from Beth-lehem, and said to the reapers, “YHWH be with you.” And they answered him, “YHWH bless you.”
Being a good man Boaz came to see how the reaping was going, and greeted his reapers with the words, ‘YHWH be with you' (compare our ‘goodbye' which means ‘God be with you'). They in return called down on him the blessing of YHWH. We are intended by this to see Boaz as a godly man. Note that in the Hebrew it literally reads, ‘YHWH be with you -- bless you, YHWH' with the Name of YHWH forming an inclusio. YHWH is brought into the centre of the situation.