The meaning of Genesis 12:3 is much controverted. This study, considering the final form of Genesis, argues that it is in the first place a promise of security and greatness to Abraham and Israel, but that in its context, following Genesis 1-11, it also indicates a divine plan to extend blessing to all the earth's peoples. In receiving God's blessing, Abraham/ Israel act as models and/ or pioneers of blessing for others. God's actions remain free, but also invite appropriate human response. Examination of the near-parallels to Genesis 12:3a in Genesis 27:29b and Numbers 24:9b shows that they are concerned more with the security of the person blessed than with the possibility of others gaining blessing. Detailed discussion of the Hebrew niphal concludes that it normally has either passive or 'middle' force (and is very rarely reflexive). No 'middle' sense found elsewhere for the niphal plausibly fits and hence the niphal in Genesis 12:3 (and 18:18 and 28:14) ispassive: analysis of these passages in their contexts supports this grammatical conclusion. The hithpael in general this study argues to be usually 'middle' in force, though sometimes passive and occasionally reflexive. The hithpael of V"[n2 when used outside Genesis is probably a 'speech action middle', meaning 'utter blessing', and this sense fits Genesis 22:18 and 26:4: this is argued to be compatible with understanding the niphal as a passive. The semantics of are also discussed. 'Blessing' in the Old Testament essentially relates to divine bestowal of prosperity onto humans, though God grants humans in certain circumstances the privilege of invoking his blessing on others. (The sense of also extends to, for example, greeting and to praising God.)