The verse you are attempting to make reference to is found below.
No interpretation is necessary for those who can read.
Galatians 3:16
(CJB) Now the promises were made to Avraham and to his seed. It doesn't say, "and to seeds," as if to many; on the contrary, it speaks of one -- "and to your seed" -- and this "one" is the Messiah.
(ESV) Now the promises were made to Abraham and to his offspring. It does not say, "And to offsprings," referring to many, but referring to one, "And to your offspring," who is Christ.
(Geneva) Nowe to Abraham and his seede were the promises made. Hee saith not, And to the seedes, as speaking of many: but, And to thy seede, as of one, which is Christ.
(Greek NT TR) τω δε αβρααμ ερρηθησαν αι επαγγελιαι και τω σπερματι αυτου ου λεγει και τοις σπερμασιν ως επι πολλων αλλ ως εφ ενος και τω σπερματι σου ος εστιν χριστος
(GW) The promises were spoken to Abraham and to his descendant. Scripture doesn't say, "descendants," referring to many, but "your descendant," referring to one. That descendant is Christ.
(LITV-TSP) But the promises were spoken to Abraham and to his Seed (it does not say, And to seeds, as of many, but as of one, "And to your Seed," which is Christ). Gen. 12:7, 13:15; 17:7, 8; 24:7
(KJV) Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
(KJV+) NowG1161 to AbrahamG11 andG2532 hisG846 seedG4690 were theG3588 promisesG1860 made.G4483 He saithG3004 not,G3756 AndG2532 to seeds,G4690 asG5613 ofG1909 many;G4183 butG235 asG5613 ofG1909 one,G1520 AndG2532 to thyG4675 seed,G4690 whichG3739 isG2076 Christ.G5547
(NKJV) Now to Abraham and his Seed were the promises made. He does not say, "And to seeds," as of many, but as of one, "AND TO YOUR SEED," who is Christ.
(YLT) and to Abraham were the promises spoken, and to his seed; He doth not say, 'And to seeds,' as of many, but as of one, 'And to thy seed,' which is Christ;
.............................................
Circumcision of the heart applies to those in the New Covenant, through their individual faith in Christ. It is not about their grandparents.
Act 2:36 Therefore let all the house of Israel know assuredly, that God hath made that same Jesus, whom ye have crucified, both Lord and Christ.
Act 2:37 Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do?
Rom 2:28 For he is not a Jew, which is one outwardly; neither is that circumcision, which is outward in the flesh:
Rom 2:29 But he is a Jew, which is one inwardly; and circumcision is that of the heart, in the spirit, and not in the letter; whose praise is not of men, but of God.
.
Grannies get fed up with it too?
