The rest of Christians is attained by faith.
Hebrews 4:1 Let us therefore fear, lest, a promise being left of entering into his rest, any one of you might seem to have failed [of it]. Hebrews 4:2 For indeed we have had glad tidings presented to us, even as they also; but the word of the report did not profit *them*, not being mixed with faith in those who heard. Hebrews 4:3 For we enter into the rest who have believed; as he said, As I have sworn in my wrath, If they shall enter into my rest; although the works had been completed from [the] foundation of [the] world. Hebrews 4:4 For he has said somewhere of the seventh [day] thus, And God rested on the seventh day from all his works: Hebrews 4:5 and in this again, If they shall enter into my rest. Hebrews 4:6 Seeing therefore it remains that some enter into it, and those who first received the glad tidings did not enter in on account of not hearkening to the word, Hebrews 4:7 again he determines a certain day, saying, in David, 'To-day,' after so long a time; (according as it has been said before), To-day, if ye will hear his voice, harden not your hearts. Hebrews 4:8 For if Jesus had brought them into rest, he would not have spoken afterwards about another day. Hebrews 4:9 There remains then a sabbatism to the people of God. Hebrews 4:10 For he that has entered into his rest, he also has rested from his works, as God did from his own. Hebrews 4:11 Let us therefore use diligence to enter into that rest, that no one may fall after the same example of not hearkening to the word.
The power of God's Word.
Hebrews 4:12 For the word of God [is] living and operative, and sharper than any two-edged sword, and penetrating to [the] division of soul and spirit, both of joints and marrow, and a discerner of the thoughts and intents of [the] heart. Hebrews 4:13 And there is not a creature unapparent before him; but all things [are] naked and laid bare to his eyes, with whom we have to do.
By our high priest Jesus the Son of God, subject to infirmities, but not sin,
Hebrews 4:14 Having therefore a great high priest who has passed through the heavens, Jesus the Son of God, let us hold fast the confession. Hebrews 4:15 For we have not a high priest not able to sympathise with our infirmities, but tempted in all things in like manner, sin apart.
we must and may go boldly to the throne of grace.
Hebrews 4:16 Let us approach therefore with boldness to the throne of grace, that we may receive mercy, and find grace for seasonable help.