1 Nephi 14

As the angel continued to show Nephi the events that would transpire in the last days, Nephi writes -

"...I, Nephi, beheld the power of the Lamb of God, that it descended upon the saints of the church of the Lamb, and upon the covenant people of the Lord, who were scattered upon all the face of the earth; and they were armed with righteousness and with the power of God in great glory."  (Book of Mormon | 1 Nephi 14:14)

Yesterday, I mentioned that in order to receive the highest degrees of glory (celestial), one must enter in and keep sacred covenants.  Obtaining other degrees of glory do not require such.

It is specifically revealed to Nephi that only the covenant people or those that have entered into and keep sacred covenants will be those in the last days that shall be "armed with righteousness and with the power of God in great glory". 

In modern day the saints were told that those that would enter into sacred covenants and ordinances would be endowed with power for  -

"Yea, verily I say unto you, I gave unto you a commandment that you should build a house, in the which house I design to endow those whom I have chosen with power from on high..."  (Doctrine and Covenants | Section 95:8)

It is within sacred temples that we are endowed with such power as we enter into and keep sacred covenants.