Charles Spurgeon Commentary Romans 4:16

"For this cause [it is] of faith, that [it may be] according to grace; to the end that the promise may 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 (ASV)

Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed;

That is, to all believers, who are the true seed of Abraham. He is the father of the faithful, and if you are one of the faithful, he is your father; and the covenant which God made with Abraham and his seed was made with you, and on your account, if you are indeed a believer in the Lord Jesus Christ.

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,

Abraham is the father of all who believe, whether they are circumcised or not; and the promises made to him belong to them also.

Therefore it is of faith, that it might be by grace: (Romans 4:16)

Salvation is by faith alone, that it may be seen to be of the free favor of God, that we may not look to merit or look to human strength, but may look away to the abounding mercy of God in Christ Jesus.