The Letter to the Hebrews recalls how Abraham trusted God's promise to him and so obtained it. St. Agnes, a 4th century martyr, also trusted God and witnessed her faith to the end, and so obtained the promise of salvation. We should seek that which allows us to trust God's promise and we will find peace, and joy, and ultimately, salvation.
Based on Hebrews 6:10-20:
God is not unjust; he will not overlook your work and the love that you showed for his sake in serving the saints, as you still do. And we want each one of you to show the same diligence, so as to realize the full assurance of hope to the very end, so that you may not become sluggish, but imitators of those who through faith and patience inherit the promises.
When God made a promise to Abraham, because he had no one greater by whom to swear, he swore by himself, saying, ‘I will surely bless you and multiply you.’ And thus Abraham, having patiently endured, obtained the promise. Human beings, of course, swear by someone greater than themselves, and an oath given as confirmation puts an end to all dispute. In the same way, when God desired to show even more clearly to the heirs of the promise the unchangeable character of his purpose, he guaranteed it by an oath, so that through two unchangeable things, in which it is impossible that God would prove false, we who have taken refuge might be strongly encouraged to seize the hope set before us. We have this hope, a sure and steadfast anchor of the soul, a hope that enters the inner shrine behind the curtain, where Jesus, a forerunner on our behalf, has entered, having become a high priest for ever according to the order of Melchizedek.
(New Revised Standard Version Bible: Anglicized Edition, copyright © 1989, 1995 National Council of the Churches of Christ in the United States of America. Used by permission. All rights reserved worldwide. http://nrsvbibles.org)