Hebrews 12:14 Make every effort to live in peace with everyone and (make every effort to be *holy); without holiness no one will see the Lord.

This is addressing “earthly consequences” not our salvation. This concerns our living experience on this earth. We do not come before the Lord in our holiness for our salvation. We come to the Lord as those separated from God to be cleansed by HIS blood that HE shed on the cross. After salvation God teaches us to behave in a holy manner as stated in Hebrews 12:10. Therefore as believers we make every effort to let God live through us.  *Holiness means to be set apart for God. We make a decision to experience holiness by hearing God and letting HIM work through us.