This is a misinterpretation of a passage in Galatians:
Gal 6:15 For in Christ Jesus neither circumcision availeth any thing, nor uncircumcision, but a new creature. Gal 6:16 And as many as walk according to this rule, peace be on them, and mercy, and upon the Israel of God.
Paul uses Abraham Isaac and Jacob to describe the place of Christ in the Christian life.
In Galatians 3 he argues that we are heirs together with Abraham because we are in His seed, which is Christ, who is the Heir of the promise.
In Galatians 4 He argues that as those who are heirs by faith, we are like Isaac, and those that insist on law keeping for either justification or sanctification are like Ishmael (Gal 4:28-29) and will persecute the children of the promise.
In Galatians 5 and 6, he argues that sowing to the religious flesh will bring all kinds of strife and other works of the flesh, and that we need to walk according to the Spirit. In this context, He is referring to Jacob, who is Israel.
In Genesis, Jacob wrestled with God and prevailed demanding a blessing that was already promised to him (Gen 32:24-26). God weakened his thigh so that he would walk with a limp the rest of his life, and named him Israel (Gen 32:27-28) In Type, Jacob was strong (in the flesh), but Israel was weak (needing to depend on God). This is a picture of our life of walking in the Spirit, not according to the strength of the flesh, but in “weakness” depending on the Spirit to produce His fruit.
This verse cannot be used to say that we are spiritual Israel, but that Jacob’s transformation through weakness is a picture of the “true circumcision” who have no confidence in the flesh (Phil 3:3) in contrast to the evil workers that want to make a show in their flesh but are enemies of the cross (Phil 2:2; Gal 6:12; Phil 3:18)