Here's a paragraph from what I read the other day.
It is not God's design that men should obtain assurance in any other way than by mortifying corruption, and increasing in grace, and obtaining the lively exercises of it. And although self-examination be a duty of great use and importance, and by no means to be neglected, yet it is not the principal means by which the saints do get satisfaction of their good estate. Assurance is not to be obtained so much by self-examination as by action. The Apostle Paul sought assurance chiefly this way, even by "forgetting the things that were behind, and reaching forth unto those things that were before, pressing towards the mark for the prize of the high calling of God in Christ Jesus; if by any means he might attain unto the resurrection of the dead." And it was by this means chiefly that he obtained assurance: 1 Cor. 9:26, "I therefore so run, not as uncertainly." He obtained assurance of winning the prize, more by running than by considering. The swiftness of his pace did more towards his assurance of a conquest than the strictness of his examination.
-- Jonathan Edwards, from The Religious Affections p. 123 (italics original)
Something I would do well to remember.