The promise, that he should be the heir of the world - Is the same as that he should be "the father of all nations," namely, of those in all nations who receive the blessing.  The whole world was promised to him and them conjointly.  Christ is the heir of the world, and of all things; and so are all Abraham's seed, all that believe in him with the faith of Abraham (John Wesley)

The nature of sacraments in general: they are signs and seals - signs to represent and instruct, seals to ratify and confirm.  Matthew Henry

Faith was reckoned to Abraham for justification, as we read Genesis 15:6, (see the note on Genesis 15:6); but circumcision was not instituted till about fourteen or fifteen years after, Genesis 17:1, etc.; for faith was reckoned to Abraham for righteousness or justification at least one year before Ishmael was born; compare Genesis 15, and 16. At Ishmael’s birth he was eighty-six years of age, Genesis 16:16; and, at the institution of circumcision, Ishmael was thirteen, and Abraham ninety-nine years old. Dr. Adam Clark

This blessedness - This happy state or condition. This state of being justified by God, and of being regarded as his friends. This is the sum of all blessedness; the only state that can be truly pronounced happy.  Dr. Albert Barnes

To be makários, blessed, is equivalent to having God's kingdom within one's heart...Makários is the one who is in the world yet independent of the world. His satisfaction comes from God and not from favorable circumstances. (The Complete Word Study Dictionary, General Editor: Spiros Zodhiates, Th.D.)

"Salvation as an accomplished fact, as a present process, and as a future prospect." Arthur W. Pink, A Fourfold Salvation

The new diet plan, More of Jesus and Less of Me!

Sola Fide - Salvation comes only through faith in Jesus and not good works (in particular the belief in atonement for sins at the cross and the resurrection of Christ)

“’Twas for my sins my dearest Lord.
Hung on the cursed tree.
And groan’d away his dying life,
For thee, my soul, for thee.
“O how I hate those lusts of mine.
That crucified my Lord;
Those sins that pierc’d and nail’d his flesh.
Fast to the fatal wood.
“Yes, my Redeemer, they shall die,
My heart hath so decreed;
Nor will I spare the guilty things.
That made my Saviour bleed.”

So we see then that our faith is unfurled and waves brightly in the wind of Christ's good pleasure.  It is Him alone who gives us strength.  It is Him alone who is worthy of our praise.  It is Him alone who is the author and finisher of this faith unfurled.  Sola de Christos!