I came across some commentary that I'm not going to include in my sermon, but that's too good to keep to myself. Enjoy:
The parable of the wild wheat is unique to Matthew (cf. Matt. 36-43). Here is an interesting paragraph from New International Dictionary of New Testament Theology (NIDOTTE), vol. 1, p. 299.
"The idea of the invisible church is found in Augustine, City of God; Wycliffe, De ecclesia; Luther, Preface to Revelation; Calvin, Institutes IV 1 7; and many other writers (see edition of Calvin's Institutes, ed. J. T. McNeill, 1960, II 1022). The thought that is uppermost is not to minimize the importance of church membership, but to recognize the possibility of hypocrisy and deceit. In the last analysis, those who belong to God are visible to God alone. Membership of the true church is a fact which is not visible to man. The idea recalls the statement of 2 Tim. 2:19; 'The Lord knows who are his.' It extends to the church what Paul says of Israel, that they are not all Israel who belong to Israel, but only 'the children of promise' (Rom. 9:6 f.). It recognizes the danger, which church members are warned against, of reaping corruption through sowing to the flesh (Gal. 3:7; cf. Rom. 8:12 f.). Paul recognized the need for discipline in his own life lest he should become a castaway (1 Cor. 10:27; cf. Phil. 2:12, 19). The possibility of church members falling away is one of great themes of Hebrews (cf. Heb. 2:3; 3:7-4:14; 6:1-12; 10:26-39; 12:12-28). It is also suggested by the parables of the weeds (Matt. 13:24-43) and the sheep and goats (Matt. 25:31-46) and the example of Judas (Matt. 10:4; 26:14, 25, 47 ff.; 27:3; Mk. 14:10, 43; Lk. 6:16; 22:3, 47; Jn. 13:2; 17:12; 18:22 ff.; Acts 1:17 ff., 25)."
These warnings do not jeopardize security, but give a balance to excessive confidence in an initial decision and ignores the mandate of discipleship and perseverance.I put the last sentence in bold because for too long in the American church we've put "excessive confidence in an initial decision" to follow Jesus. But following Jesus is more than praying a prayer. It's about following him for a lifetime.
Hope that inspires some thought on this Monday morning.