Conventional: Giving is the opposite of receiving, for what you give you lose (see sacrifice). Giving, therefore, is usually a subtle way to obligate someone to give you something back, something more valuable than what you gave away (see W-pI.105.1-2). The Course calls this “giving to get” (T-4.II.6:5), and says that what is really given in this case is guilt.
ACIM: “…giving and receiving are the same” (this line occurs six times in the Course; see T-25.IX.10:6). The real gift is not the physical thing, which you do lose, but the idea of love behind it. And when you give an idea, you do not lose it (see T-5.I.1-2). Rather, it increases as it is shared with others. Moreover, you will not recognize what you have received until you give it, for giving is the proof of having. Your gift proves that you have an idea and that you deserve to receive it. According to the Course, this is one of its most important and most radical concepts (see W-pI.105.3:10, W-pI.126.1 and M-4.VII.1:6-8). See extension, function, healing, teaching, witness.