What does adoption really mean according to this teaching?

Les explains that when a son reached the age and was ready for that position with the father, they went through the rites of adoption. The word really means we are placed as a full son—not just one born into the family, and not one legally taken from another family—but a son who has gone through the training years, been prepared and tutored, and is now placed as a full partner with the Father. The glory is that the moment we are saved, we are born into the family of God, and immediately God also places us as the full heir with Jesus Christ. We do not have to work for twenty years like poor old Jacob did for his wives, or strive and strain hoping to attain this position; it happens the moment we believe, so we can say Abba Father. At salvation we are born into the family of God by the work of the Holy Spirit, but another act of God places us as a full heir. If we are children, then we are heirs—not just an heir down the line hoping for a little inheritance, but joint heirs. Even in our own culture, a joint heir implies equality: what is His is hers, and vice versa.