It is another thing than many are aware of

Sinclair Ferguson, recounting the way John Owen came to know assurance of salvation 400 years ago:

The life of Richard Davis, minister in Rothwell, Northamptonshire, provides a rare insight into the autobiographical nature of Owen's exposition.

Davis had sought out Owen for spiritual counsel and arranged an interview with him. In the course of conversation, Owen asked him, 'Young man, pray in what manner do you go to God?'

'Through the Mediator, sir,' answered Davis.

'That is easily said,' replied Owen, 'but I assure you it is another thing to go to God through the Mediator than many who make use of the expression are aware of. I myself preached Christ some years, when I had but very little, if any, experimental acquaintance with access to God through Christ; until the Lord was pleased to visit me with sore affliction, whereby I was brought to the mouth of the grave, and under which my soul was oppressed with horror and darkness; but God graciously relieved my spirit through a powerful application of Ps 130.4, But there is forgiveness with thee that thou mayest be feared, from whence I received special instruction, peace, and comfort, in drawing near to God through the Mediator, and preached thereupon immediately after my recovery.'

--Sinclar Ferguson, John Owen on the Christian Life (Banner of Truth, 1987), 100 n. 1

By the way: this new awareness of happy nearness to God was not an isolated existential event after which Owen turned once more to dry theologizing. Volume six of Owen's Works devotes a dense 200 pages to a single verse to expound assurance of salvation--Psalm 130:4.

When John Owen writes on indwelling sin, temptation, mortification, the Holy Spirit, assurance of salvation--all he is doing is using the Bible to make sense of personal experience (see also pp. 123-24). I find that very comforting. And a model for the rest of us.