The father's response to his son is seen in verses 22 through 24. "But the father said to his slaves, Bring out quickly the best robe and put it on him, and put a ring on his hand and sandals on his feet. And bring the fattened calf; slaughter it, and let us eat and be merry, because this son of mine was dead and lives again; he was lost and has been found. And they began to be merry." The son came back as a poor, pitiful prodigal, but the father gave him three things: a robe, a ring, and sandals. The father clothed his son with the best robe to cover him. This robe signifies Christ as our righteousness for our justification (Jer. 23:6; 1 Cor. 1:30; cf. Isa. 61:10; Zech. 3:4). The ring signifies the sealing Spirit as the God-given seal upon the accepted believer (Eph. 1:13). If someone is wearing a gold ring, he must have a lot of money. The ring on the son's finger was a mark that he had become rich. The sandals signify the power of God's salvation to separate the believers from the dirty earth.
Now he was no longer a poor prodigal, but a rich young man. He was now qualified to enter the father's house, but he needed something to eat. He had been eating the carob pods which the hogs were eating (Luke 15:16) and he had walked quite a distance to his father's house without eating anything. He was clothed with a robe, marked with a ring, and separated from the earth with a pair of shoes, but his stomach surely was crying out for food. So the father told his slaves to kill the fattened calf for his son's enjoyment (v. 23). This signifies the rich Christ (Eph. 3:8), killed on the cross for the believers' enjoyment. After we are justified by God with Christ, we receive Christ as our satisfaction, as our supply, as the fattened calf.
Thus, Christ here is first a robe and then the fattened calf. In resurrection He has become our food, our life supply. This is the result of the seeking and convicting of the Spirit. The seeking and convicting of the Spirit issue in our obedience, in our repentance and faith. Eventually, we receive Christ outwardly as our righteousness and inwardly as our life and life supply. This is the sanctification of the Spirit, the first step of God's salvation.