Isaac lived a life of inheriting and restfully enjoying all his father’s riches. He was born of grace, grew up in grace, and became the heir in grace (Gen. 21:9-12), inheriting all that his father had (Gen. 25:5). Furthermore, he inherited God’s promise to his father, especially the promise concerning Christ, in whom all the nations of the earth would be blessed (Gen. 26:3-5). His entire life was a resting and enjoying life. He was always resting. At a time when he had lost his mother, did not yet have a wife, and his servant had gone away from him, he was not troubled. Rather, he went to the field to meditate (Gen. 24:63). When he encountered the trouble with the Philistines over the wells, he remained restful and did not contend with them (Gen. 26:18-22). He was not merely resting; he was also enjoying. His father and his father’s servant did everything to prepare a bride for him (Gen. 24:61-67). During his whole life, he never suffered thirst. Wherever he went, even when he went downward, going south to the land of the Philistines, there was always a well for his enjoyment. Whenever he sowed in the land, he received a hundredfold. He became great and continued to grow greater until he became very great (Gen. 26:12-14). When he was old, he still asked Esau to go out to the field to get some venison for him and make him savory meat, which he loved (Gen. 27:1-4). Throughout his whole life he did not do anything by his own effort. From the beginning to the end, he was a man who inherited his father’s possessions (Gen. 25:5) and restfully enjoyed all his father’s riches. Isaac represents the New Testament believers, who do not need to strive to accomplish something and who need only to inherit the grace in Christ and enjoy the unlimited grace of God (1 Cor. 15:10).
First, God gave the promise to Abraham, Isaac’s father, saying that He would make him a blessing to all the nations of the earth. Later, He gave the same promise to Isaac to confirm in him what He had promised to Abraham (Gen. 26:3-4). The focus of this promise was Christ in God’s economy, in whom all the nations of the earth would be blessed (Gal. 3:16). The blessing that Christ gives to all the nations of the earth is the Triune God, who is embodied in Him. This Triune God in Christ, through Christ’s becoming the all-inclusive Spirit, is received and enjoyed as the greatest blessing in the universe by all those on earth who have believed into Christ (Gal. 3:14).
According to Genesis 21, after Isaac had grown up and was weaned, Ishmael began to mock him (v. 9). This means that Ishmael persecuted Isaac. God considered this persecution the beginning of the four-hundred-year persecution of His people, the Israelites (Gen. 15:13; Acts 7:6). Isaac was born according to the Holy Spirit and through the promise, whereas Ishmael was born according to the flesh and through the natural strength. As it was then, that he who was born according to flesh persecuted him who was born according to Spirit, so also it is now (Gal. 4:29). Therefore, Isaac’s suffering of Ishmael’s persecution signifies that the believers, who are born according to the Spirit of grace in the New Testament, will suffer persecution from those who are born according to flesh (Gal. 4:29).
After Isaac had grown up, in order to test Abraham, God told him to bring Isaac to the appointed mountain and to offer him as a burnt offering. By faith Abraham offered Isaac. After Isaac was laid upon the altar on the wood, as Abraham stretched forth his hand and took the knife to slay him, God prepared a ram as Isaac’s substitute (Gen. 22:2-13). In this way, Isaac was offered as a burnt offering and thus experienced death and resurrection. This signifies that the New Testament believers also must be offered as a burnt offering and experience death and resurrection. When the New Testament believers, constrained by the Lord’s love, present their bodies as a living sacrifice (Rom. 12:1), a sacrifice of resurrection and life, they experience co-crucifixion with Christ (Gal. 2:20a). Thus, they live a crucified life by being conformed to Christ’s death, and thereby know and experience Christ and the power of His resurrection (Phil. 3:10). Eventually, they will attain to the out-resurrection from among the dead (Phil. 3:11).