Hebrews 10:22-27 “let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled clean from an evil conscience and our bodies washed with pure water. 23 Let us hold fast the confession of our hope without wavering, for He who promised is faithful; 24 and let us consider how to stimulate one another to love and good deeds, 25 not forsaking our own assembling together, as is the habit of some, but encouraging one another; and all the more as you see the day drawing near. 26 For if we go on sinning willfully after receiving the knowledge of the truth, there no longer remains a sacrifice for sins, 27 but a terrifying expectation of judgment and the fury of a fire which will consume the adversaries.”[i]
In Hebrews 10:22, the writer (presumably Paul) tells his Christian audience, which was apparently composed of some whose Christianity may have been in doubt, to come near to Christ with “a sincere heart”. He admonishes the “sincere” believers to remain faithful, love one another, perform good works, encourage one another, assemble together corporately (Heb 10:23-25). These characteristics, therefore, are indicators by which the faithful today can be more clearly identified. In the same way, churches which teach, practice, and admonish their members to do these things will also likely be true houses of worship.
Given the overwhelming prevalence of false teachers, finding a good place to commune with fellow believers in authentic worship has become increasingly challenging. Paul’s warning in 1 Timothy 4:1-2 seems to have pointed to this contemporary period more so than ever before: “But the Spirit explicitly says that in later times some will fall away from the faith, paying attention to deceitful spirits and doctrines of demons, by means of the hypocrisy of liars seared in their own conscience as with a branding iron.” Here, these apostates are shown to be a part of the church (in some way) and yet they fall away proving their insincerity of their confession of faith. Instead of following the doctrines of Scriptures carefully, they readily absorb the deceitful rhetoric of false teachers who tell them what they want to hear (cf. 2 Tim 4:3).
In Hebrews 10:26, the writer offers a clearer picture of those who lack sincerity in their faith. Though being fully aware of the mercy offered in Christ, these apostates prefer to continue to practice sin. While all people including Christians sin, these denouncers actively pursue and practice sin failing to put to death the misdeeds of their flesh (cf. Romans 8:13). For those of whom this is true, Hebrews 10:29 warns of an even greater eternal punishment.
[i]All biblical quotes come from NASB1995.