The Apostle Peter wrote in his first letter:

As obedient children, do not be conformed to the passions of your former ignorance, but as he who called you is holy, you also be holy in all your conduct, since it is written, “You shall be holy, for I am holy.” 1 Peter 1:14-16 English Standard Version (ESV)

John Calvin comments on these verses:

He who hath called you is holy – He reasons from the end for which we are called. God sets us apart as a peculiar people for himself; then we ought to be free from all pollutions…

Calvin, stating the obvious, that we are not capable of being like God in holiness, nevertheless, points out:

…We ought daily to strive more and more. And we ought to remember that we are not only told what our duty is, but that God also adds, “I am he who sanctify you.”

The Calvin presses the point further:

It is added: in all manner of conversation, or, in your whole conduct. There is then no part of our life which is not to be redolent with this good odour of holiness…

You may currently stink at holy conduct. However, if you are in Christ and He is in you, then you must make great efforts to achieve or obtain it:

Strive for peace with everyone, and for the holiness without which no one will see the Lord. Hebrews 12:14 (ESV)

To this verse, Calvin comments with regard to those who profess Christ as Lord:

Follow peace, etc. – Men are so born that they all seem to shun peace; for all study their own interest, seek their own ways, and care not to accommodate themselves to the ways of others. Unless then we strenuously labor to follow peace, we shall never retain it; for many things will happen daily affording occasion for discords…

And, with regard to those outside of Christ, Calvin says:

As however peace cannot be maintained with the ungodly except on the condition of approving of their vices and wickedness, the Apostle immediately adds, that holiness is to be followed together with peace; as though he commended peace to us with this exception, that the friendship of the wicked is not to be allowed to defile or pollute us; for holiness has an especial regard to God…

Finally, Calvin adds:

He declares, that without holiness no man shall see the Lord; for with no other eyes shall we see God than those which have been renewed after his image.

As scripture teaches, we know everyone born from above practices right behavior.

Last Judgment, 1537 – 1541, Michelangelo and assistants, the Sistine Chapel in the Vatican, PD-Art-US