What the Bible calls a “psychological edge”

Most are familiar with, at most, one hymn by Augustus Toplady, Rock of Ages. Here's another of which you should be aware. (HT Anthony Carter)

A Debtor to Mercy Alone
by Augustus Montague Toplady

A debtor to mercy alone,
Of covenant mercy I sing;
Nor fear, with Thy righteousness on,
My person and offering to bring.
The terrors of law and of God
With me can have nothing to do;
My Savior's obedience and blood
Hide all my transgressions from view.

The work which His goodness began,
The arm of His strength will complete;
His promise is yea and amen,
And never was forfeited yet.
Things future, nor things that are now,
Not all things below nor above
Can make Him His purpose forego,
Or sever my soul from His love.

My name from the palms of His hands
Eternity will not erase;
Impressed on His heart it remains
In marks of indelible grace.
Yes, I to the end shall endure,
As sure as the earnest is given
More happy, but not more secure,
The glorified spirits in heaven.
(emphasis mine)