Give is a prefix for two abilities respectively, namely Give Attack +1 (Give Attack Plus 1) and Give Health +1 (Give Health Plus 1). As of the update for Monstern Pack Release, the give health bonus has been increased to +2 but the effect is the same. As its name indicates, the ability will cause the unit to give a permanent ability to a friendly unit, before attacking in a battle cycle of an unit. The former case is Attack Plus 1 and latter is Health Plus 1. However, although the prefix is limited to artifacts, this ability works like the spell Mobilize. This means the effect remains even if the artifact with give ability is removed.
Give is dependant of the instance of the artifact in play. (Give is limited to artifacts for now) From entering in play to removal (Unsummoning works) it is considered one life cycle of a certain artifacts. In one life cycle, Give ability can only target friendly units that have not yet received benefits of the ability. That is, in long term Give Attack +1 will cause all friendly units except equipped unit to receive Attack Plus 1, and then the ability stops functioning. Any units that were removed from play and reentering again can receive benefit of Give again.
Give benefits are not erased when the artifact is removed from play. Moreover, the limiation that units can only receive one Give benefit from one artifact, is restricted to the life cycle of the artifacts. If the artifact with Give reenters play it will be treated as seperate Give ability. That means, if a hammer is reclaimed once an unit can possibly gain maximum of Attack Plus 2. Combining with the nature of targeting limitation, thereotically all units can receive Attack Plus 2 (except the equipped unit) if the hammer is reclaimed once.