2 Peter 1:5, 6:
Giving all diligence, add to your faith virtue; and to virtue knowledge, etc.
If thou wouldest enjoy the eminent grace of the full assurance of faith, under the blessed Spirit's influence, and assistance, do what the Scripture tells thee, "Give diligence." Take care that thy faith is of the right kind-that it is not a mere belief of doctrine, but a simple faith, depending on Christ, and on Christ alone. Give diligent heed to thy courage. Plead with God that He would give thee the face of a lion, that thou mayest, with a consciousness of right, go on boldly.
Study well the Scriptures, and get knowledge; for a knowledge of doctrine will tend very much to confirm faith. Try to understand God's Word; let it dwell in thy heart richly. When thou hast done this, "Add to thy knowledge temperance." Take heed to thy body: be temperate without. Take heed to thy soul: be temperate within. Get temperance of lip, life, heart, and thought. Add to this, by God's Holy Spirit, patience; ask Him to give thee that patience which endureth affliction, which, when it is tried, shall come forth as gold. Array yourself with patience, that you may not murmur nor be depressed in your afflictions.
When that grace is won look to godliness. Godliness is something more than religion. Make God's glory your object in life; live in His sight; dwell close to Him; seek for fellowship with Him; and thou hast "godliness"; and to that add brotherly love. Have a love to all the saints: and add to that a charity, which openeth its arms to all men, and loves their souls. When you are adorned with these jewels, and just in proportion as you practise these heavenly virtues, will you come to know by clearest evidence "your calling and election." "Give diligence," if you would get assurance, for lukewarmness and doubting very naturally go hand in hand.