By faith ponder on this, that ...

By faith ponder on this, that though thou art no way able in or by thyself to get the conquest over thy distemper, though thou art even weary of contending, and art utterly ready to faint, yet that there is enough in Jesus Christ to yield thee relief.
 John Owen

Quotes from the same author

Great winds and storms help fruit-bearing trees. So also do corruptions and temptations help the fruitfulness of grace and holiness. The storm loosens the earth round its roots so the tree is able to get its roots deeper into the earth, where it receives fresh supplies of nourishment. But only much later will it be seen to bring forth better fruit. So corruptions and temptations develop the roots of humility, self-abasement and mourning in a deeper search for that grace by which holiness grows strong. But only later will there be visible fruits of increased holiness.
 John Owen
For a man solemnly to undertake the interpretation of any portion of Scripture without invocation of God, to be taught and instructed by His Spirit, is a high provocation of him; nor shall I expect the discovery of truth from any one who thus proudly engages in a work so much beyond his ability.
 John Owen
I have known some good men who have been so addicted to their study, that they have thought the last day of the week sufficient to prepare for their ministry, though they employ all the rest of the week in other studies. But your business is to trade with your spiritual abilities. ... A man may preach a very good sermon, who is otherwise himself; but he will never make a good minister of Jesus Christ, whose mind and heart are not always in the work. Spiritual gifts will require continual ruminating on the things of the Gospel in our minds.
 John Owen
The duties God requires of us are not in proportion to the strength we possess in ourselves. Rather, they are proportional to the resources available to us in Christ. We do not have the ability in ourselves to accomplish the least of God's tasks. This is the law of grace. When we recognize it is impossible for us to perform a duty in our own strength, we will discover the secret of its accomplishment.
 John Owen
No heart can conceive that treasury of mercies which lies in this one privilege, in having liberty and ability to approach unto God at all times, according to his mind and will.
 John Owen