Perseverance of the Saints...in John 3:16?

Spurgeon thinks so. I see it now, too.

In a sermon titled "Immeasurable Love", which C. H. Spurgeon preached July 26th, 1885 at the Metropolitan Tabernacle, a sermon based entirely on John 3:16, he said:

[Whosoever believeth], his faith shall not perish, for this promise covers it - "Whosoever believeth in Him shall not perish." The penitent has believed in Jesus, and therefore he has begun to be a Christian; "Oh," cries an enemy, "let him alone: he will soon be back among us; he will soon be as careless as ever." Listen. "Whosoever believeth in Him shall not perish," and therefore he will not return to his former state. This proves the final perseverance of the saints; for if the believer ceased to be a believer he would perish; and as he cannot perish, it is clear that he will continue as a believer. If thou believest in Jesus, thou shalt never leave off believing in him; for that would be to perish. If thou believest in him, thou shalt never delight in thine old sins; for that would be to perish. If thou believest in him, thou shalt never lose spiritual life. How canst thou lose that which is everlasting? If thou wert to lose it, it would prove that it was not everlasting, and thou wouldst perish; and thus thou wouldst make this word to be of no effect. Whosever with his heart believeth in Christ is a saved man, not for to-night only, but for all the nights that ever shall be, and for that dread night of death, and for that solemn eternity which draws so near. "Whosoever believeth in Him shall not perish;" but he shall have a life that cannot die, a justification that cannot be disputed, an acceptance which shall never cease.