I cannot advance an inch without praying my way, nor keep the inch I gain without watching and standing fast. Grace alone can preserve and perfect me. The old nature will kill the new nature if it can; and to this moment the only reason why my new nature is not dead is this—because it cannot die. If it could have died, it would have been slain long ago; but Jesus said, "I give unto my sheep eternal life"; "he that believeth on me hast everlasting life"; and therefore the believer cannot die. The only religion which will save you is one that you cannot leave, because it possesses you, and will not leave you. If you hold a doctrine which you can give up, give it up; but if the doctrines are burnt into you so that as long as you live you must hold them, and so that if you were burnt every ash would hold that same truth in it, because you are impregnated with it, then you have found the right thing.

Immeasurable Love, A Sermon delivered by Charles Haddon Spurgeon, at the Metropolitan Tabernacle, Newington, on the evening of June 7th, 1885

The text begins with a command — it’s the only command in the text and therefore probably the main point. Verse 15a: “Do not love the world or the things in the world.” Everything else in the text is an argument, or incentive, for why we should not love the world. The first incentive John gives is that “if anyone loves the world, love for the Father is not in him” (verse 15b). In other words, the reason you shouldn’t love the world is that you can’t love the world and God at the same time. Love for the world pushes out love for God, and love for God pushes out love for the world.

—John Piper

God is the highest good of the reasonable creature. The enjoyment of him is our proper; and is the only happiness with which our souls can be satisfied. To go to heaven, fully to enjoy God, is infinitely better than the most pleasant accommodations here. Better than fathers and mothers, husbands, wives, or children, or the company of any, or all earthly friends. These are but shadows; but the enjoyment of God is the substance. These are but scattered beams; but God is the sun. These are but streams; but God is the fountain. These are but drops, but God is the ocean.

—Jonathan Edwards, from his sermon, “The True Christian’s Life, A Journey Towards Heaven

Love for the world and love for the Father are mutually exclusive. You can’t say well, I can maybe go halfsies, or I’m a Christian, there’s a lot of people who think being a Christian means you give God like 55 percent, world 45 percent, but I still give God 55 percent. No, sort of math exists here. “If you love the world the love of the Father is not in you.”

—Kevin DeYoung

“He loves thee too little who loves anything together with thee which he loves not for thy sake.

—St. Augustine