Hebrews 6:9-13

But, beloved, we are persuaded better things of you, and things that accompany salvation, though we thus speak. For God is not unrighteous to forget your work and labour of love, which ye have shewed toward his name, in that ye have ministered to the saints, and do minister. And we desire that every one of you do shew the same diligence to the full assurance of hope unto the end: that ye be not slothful, but followers of them who through faith and patience inherit the promises.
For when God made promise to Abraham, because he could swear by no greater, he sware by himself