John 8:39: Not by the Christian name alone

Not by the Christian name alone
The Christian man is show'd,
Words cannot evidence a son
Of Abraham and of God;
No confident assertions vain,
No single act can prove
That I am truly born again,
And God sincerely love.

I must in Abraham's footsteps stay,
Pursue him to the skies,
My household teach the heavenly way,
My Isaac sacrifice;
My life must speak the faith within,
In even tenour flow.
Demonstrate I am saved from sin.
And God my Father know.