Hebrews 11:32-33 KJV: And what shall I more say? for the time would fail me to tell of Gedeon, and of Barak, and of Samson, and of Jephthae; of David also, and Samuel, and of the prophets: Who through faith subdued kingdoms, wrought righteousness, obtained promises, stopped the mouths of lions,
Here the Bible tells us that some of the OT saints obtained promises by faith.
How do we do this today?
To obtain the promises of God by faith you first start by obtaining what the Bible calls the promise: this is the promise of eternal life.
I John 2:25 KJV: And this is the promise that he hath promised us, even eternal life.
Psalms 133:3 KJV: As the dew of Hermon, and as the dew that descended upon the mountains of Zion: for there the LORD commanded the blessing, even life for evermore.
Eternal life is the very substance and nature of God (Jn. 5.26). It is called living water: a spiritual liquid that circulates in God, in much the same way that blood circulates in the human body (Jn. 5.26, 4.10,14).
It is the source of all divine attributes: wisdom, love and power (2 Pet. 2.3, 4).
It is the substance that God used to create all things (Jn. 1.1-4)
So by receiving the promise of eternal life, you receive the divine power to create and bring into physical manifestation every other promise of God.
Now it is true every Christian receives eternal life when they get born-again, however we need to keep receiving and expending eternal life in greater and greater measures as we grow spiritually. Eternal life should circulate in us as it does in God: all life is from God and then goes through Him to all creation and returns back to Him as created things die or, as it were, lose their life.
Romans 11:36 KJV: For of him, and through him, and to him, are all things: to whom be glory forever. Amen.
So to obtain promises in the New Testament: by faith receive the promise of eternal life in measures by confessing with your mouth the promises in the Word that give eternal life.
An example of this is John 10.10:”I am come that they might have life and have it more abundantly”…. So to receive this promise you say “In Jesus name I receive the life of God in an abundant measure now to obtain other promises of God.”
Having done this, you can now pray in the spirit (1 Cor. 14.2, Eph. 6.18, Jude 1.20) to release this creative life of God as rivers of living water (Jn. 7. 38,39) from your belly, or spirit, that will now create or bring into physical manifestation the other promises of God you desire: healing, prosperity, protection and others.
So, by obtaining the promise of eternal life you can obtain all the other promises of God in His Word.