Here, to walk before God is to walk in His presence, constantly enjoying Him and His all-sufficient supply. To be perfect is to have God added to us as the element and factor of perfection. Practically, it means that we do not rely on the strength of the flesh but trust in God as the all-sufficient Mighty One for our life and our work.

Heb. El Shaddai. El means the Mighty One, and Shaddai comes from the Hebrew word meaning breast or udder. This divine title reveals God as the Mighty One with an udder, that is, the all-sufficient Mighty One. He is the source of grace to supply His called ones with the riches of His divine being that they may bring forth Christ as the seed for the fulfillment of His purpose.

Abraham’s producing of Ishmael by the exercise of his natural strength was a serious offense against God and His economy. Because of this, after the birth of Ishmael, Abraham’s fellowship with God was broken; God waited for thirteen years (cf. Gen. 16:16), until Abraham’s natural strength was terminated, before He came to contact Abraham again (Rom. 4:19 and note Rom. 4:19^1a). See note Gen. 15:4¹.

Meaning father of a multitude. In order to fulfill His eternal purpose, God needs not one exalted person but the father of a great multitude (cf. Gen. 1:28; 9:1). Hence, the changing of Abraham’s name, signifying the changing of his person, was for the fulfillment of God’s purpose. In spiritual experience, the real changing of a name is the change from “I” to Christ (Gal. 2:20) and from “I” to the grace of God (1 Cor. 15:10). Only Christ as God’s grace, not “I,” can bring forth the multitude needed to fulfill God’s purpose (see note Gen. 15:4¹). Cf. Gen. 32:27-28; John 1:42.

Meaning exalted father.

The mentioning of nations and kings in vv. 4-6 and in Gen. 35:11 implies that the result of our being multiplied must be the proper church life as the kingdom of God on earth (Rom. 14:17 and note Rom. 14:17^1a). See note Gen. 12:2^2a.

In figure the eighth day, the first day of a new week, refers to Christ’s resurrection (Matt. 28:1; John 20:1). Circumcision must be in resurrection, and it always ushers us into resurrection (Col. 2:12; cf. Rom. 6:3-5), making us a new person, a new creation (2 Cor. 5:17; Gal. 6:15), for the fulfillment of God’s purpose.

Circumcision corresponds to the changing of human names (v. 5). Both signify the terminating of our old being and our being brought into resurrection so that we may be no longer a natural person but a resurrected person.

Although God’s promise concerning the inheriting of the good land by His elect (Gen. 12:1-2, 7; 13:15-17) had been made a covenant (Gen. 15:4-5, 18-21), there was still the need to confirm the covenant of God’s promise with the covenant of circumcision. Circumcision was the procedure that God’s elect had to pass through in order to inherit God’s promise. It signifies that God’s chosen ones in the New Testament must be terminated through the cross so that they may inherit all the riches in Christ promised by God (cf. Gal. 2:20). See Rom. 4:11 and note Rom. 4:11¹.

The spiritual meaning of circumcision is to put off the flesh, to put off the self and the old man, through the crucifixion of Christ (Col. 2:11, 13a; Deut. 10:16; Jer. 4:4a; Acts 7:51; Gal. 5:24; Rom. 6:6; Eph. 4:22; Col. 3:9). In ch. 16 Abraham exercised his flesh to produce Ishmael. Here God asked him to cut off his flesh, to terminate his natural strength, so that God could come in and bring forth Isaac by His grace for the fulfillment of His purpose. The circumcision in the Old Testament is the equivalent of baptism in the New Testament (Col. 2:11-12 and notes). The real circumcision is not outward in the flesh but inward “of the heart, in spirit, not in letter” (Rom. 2:28-29). See note Josh. 5:2¹.

Meaning my princess.

If God’s called ones do not live a crucified life by terminating their self and their natural being, in their subjective experience they will be cut off from Christ, from the church life, and from the supply of God’s grace and will have nothing to do with God’s covenant for the fulfillment of God’s purpose (John 15:6; Gal. 5:4).

Meaning he laughs.

Ishmael, the seed produced by the flesh, was rejected by God (Gen. 21:10). Only Isaac, the seed brought forth by God’s grace, was established for the fulfillment of God’s purpose (v. 21; 21:12; Rom. 9:7-9).

See note Gen. 18:14^1b.

Meaning princess. The word my before princess (see note Gen. 17:15¹) indicates narrowness and particularity. Here, the changing of Sarah’s name signifies generality and suggests the enlarging and broadening of her person to make her a mother of nations (v. 16). As seen with both Abraham (v. 5) and Sarah, such a change requires the termination of our old and natural man so that we may be transformed into a new person who can produce seed and care for others for the fulfillment of God’s purpose.

I.e., by God’s grace in God’s covenant of promise, symbolized here by Sarah, the free woman, Abraham’s wife (Gal. 4:22-26). The birth of Isaac by Sarah signifies the begetting of the believers in Christ by God’s grace in the resurrection of Christ (1 Pet. 1:3) to be the legal seed of Abraham (Gal. 4:28, 31; 3:29). God’s covenant of circumcision in this chapter corresponds to the new covenant, in which Christ’s death cuts off our old man in the flesh and Christ’s resurrection germinates our new man, signified by Isaac, to make us the new creation (2 Cor. 5:17).