The rest of Christians is attained by faith.
Hebrews 4:1 Let us therefore fear, lest a promise being left [us] of entering into his rest, any of you should seem to come short of it. Hebrews 4:2 For to us was the gospel preached, as well as to them: but the word which they heard did not profit them, not being mixed with faith in them that heard [it]. Hebrews 4:3 For we who have believed do enter into rest, as he said, As I have sworn in my wrath, if they shall enter into my rest: although the works were finished from the foundation of the world. Hebrews 4:4 For he spoke in a certain place of the seventh [day] on this wise, And God rested the seventh day from all his works. Hebrews 4:5 And in this [place] again, If they shall enter into my rest. Hebrews 4:6 Seeing therefore it remaineth that some must enter into it, and they to whom it was first preached entered not because of unbelief: Hebrews 4:7 (Again, he limiteth a certain day, saying in David, To-day, after so long a time; as it is said, To-day, if ye will hear his voice, harden not your hearts. Hebrews 4:8 For if Jesus had given them rest, then he would not afterward have spoken of another day. Hebrews 4:9 There remaineth therefore a rest to the people of God. Hebrews 4:10 For he that hath entered into his rest, he also hath ceased from his own works, as God [did] from his.) Hebrews 4:11 Let us labor therefore to enter into that rest, lest any man fall after the same example of unbelief.
The power of God's Word.
Hebrews 4:12 For the word of God [is] living, and powerful, and sharper than any two-edged sword, piercing even to the dividing asunder of soul and spirit, and of the joints and marrow, and [is] a discerner of the thoughts and intents of the heart. Hebrews 4:13 Neither is there any creature that is not manifest in his sight: but all things [are] naked and opened to the eyes of him with whom we have to do.
By our high priest Jesus the Son of God, subject to infirmities, but not sin,
Hebrews 4:14 Seeing then that we have a great High Priest, that hath passed into the heavens, Jesus the Son of God, let us hold fast [our] profession. Hebrews 4:15 For we have not a high priest who cannot be touched with the feeling of our infirmities; but who was in all points tempted as [we are], [yet] without sin.
we must and may go boldly to the throne of grace.
Hebrews 4:16 Let us therefore come boldly to the throne of grace, that we may obtain mercy, and find grace to help in time of need.