The English translation is misleading because the Greek doesn't say "the Holy Ghost."  It says
a breath sacred" or, more simply, "a pure breath."  Reading this outside of Christian history, I would assume that he meant the breath of a resurrected man, free from the biological impurities of life. The word translated as "ghost" primarily means "breath" but is used to means "spirit" in the sense we say "breath of life."  Jesus clearly uses it elsewhere to refer to "spirit" or "soul," as it is sometimes translated, but by breathing out, Jesus emphasizes its meaning of "breath" perhaps as a play on words.  The article "the" is added to make it seem like a reference to the third person of the Trinity. A "the" is usually used before primary names, but it isn't used here.

The word translated as "receive" primarily means "take." However, it means "receive" in the same sense that we use "get" to mean "receive" and has many different uses as we use "get" in English. Among these are the ideas of "understanding" and "possessing." Here the form is either a statement about what happens at some point in time or a command. It seems more like a command.