This appeal to spiritual watchfulness is a call to the church as a whole. The exhortation "see to it that no one misses the grace of God" (12:15a) is a key statement. Remaining steadfast in faith (10:19–11:40), enduring discipline as children (12:1–13), and pursuing peace and holiness (12:14) are all related to the grace of God, as is everything involving our salvation. If entrance into the Christian life is by the grace of God, even so the continuance and completion of it is by the grace of God. The dreadful possibility of missing God's grace is not because his grace is inaccessible, but because some may choose not to avail themselves of it. For this reason it is possible for a person (though once a believer) not to reach the goal that is attainable only by his grace operating through faith (cf. 3:12; Bruce, 1990, 349). Marshall makes several observations concerning this warning passage (1969, 149–51). (1) It is possible for a believer to draw back from the grace of God (12:15a; cf. 2 Cor. 6:1; Gal. 5:4). The context of the warning here, as elsewhere in Hebrews (e.g., Heb. 2:1–4; 6:4–8; 10:26–31), indicates that a true believer is meant. (2) Where the grace of God is missed, bitterness will take root and potentially defile other members in the church (12:15b). The deadly sins of unbelief and a poisonous root of bitterness function like a fatally contagious disease that can "defile many" in the community. (3) No one should be "sexually immoral ["pornos"; lit., fornicator] or ... godless like Esau." Esau was a sensual man rather than a spiritual man—entirely earthly-minded rather than heavenly-minded—who traded away "his inheritance rights as the oldest son" (12:16b) for the momentary gratification of his physical senses. He represents those who would make the unthinkable exchange of long-range spiritual inheritance (i.e., things hoped for but not yet seen, 11:1) for present tangible and visible benefits, momentary though they be. Afterwards, when Esau realized the foolishness of his choice, he wanted to inherit his blessing but could not since "he was rejected" by God (12:17a).