Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all… – Romans 4:16

There is a relation between us and Abraham even as Paul assures us in the epistle to the Galatians, “Know ye therefore that they which are of faith, the same are the children of Abraham.” Something, surely, is expected of the children of such a man as Abraham. O, for shame, thou unbelieving one! Is Abraham thy father? Art thou one of the faithful seed? Great mountains are often succeeded by low valleys. Perhaps that is the case with you; but it should not be so. The natural seed were cut off because they had no faith, let not those who are grafted in, think to do without it. It is by faith that you are a son at all. You disprove your pedigree if you tolerate unbelief. Oh! let nobody find fault with Abraham through you, and surely they may do so if they find you staggering. That staggering is a shocking business: staggering at God’s promises is terrible. Abraham staggered not at the promise through unbelief. May we never dishonour the right noble grace of faith, but so believe that all men may know Abraham’s God to be our God. O for abounding spiritual life, for the God of Abraham is not the God of the dead but of the living; and we can only live unto God by faith.

Brethren, because we are the seed of Abraham, the apostle declares that the blessing of Abraham has come upon us also. I pray that all the friends and labourers may grasp the blessing of Abraham. What is it? It is a covenant favour that belongs to all who are the servants of God by faith. Here is the substance of it: “Surely blessing, I will bless thee, and in multiplying, I will multiply thee.” That is the grand old covenant promise and it belongs to the church. ~ C.H. Spurgeon

https://www.blueletterbible.org/Comm/spurgeon_charles/sermons/1596.cfm