For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life. (John 3:16)
Of all the stars in the sky, the polestar is the most useful to the mariner. This text is a polestar, for it has guided more souls to salvation than any other Scripture. It is among promises what the Great Bear is among constellations.
Several words in it shine with peculiar brilliance. Here we have God’s love with a “so” to it, which marks its measureless greatness. Then we have God’s gift in all its freeness and greatness. This also is God’s Son, that unique and priceless gift of a love which could never fully show itself till heaven’s Only-begotten had been sent to live and die for men. These three points are full of light.
Then there is the simple requirement of believing, which graciously points to a way of salvation suitable for guilty men. This is backed by a wide description—”whosoever believeth in him.” Many have found room in “whosoever” who would have felt themselves shut out by a narrower word. Then comes the great promise, that believers in Jesus shall not perish but have everlasting life. This is cheering to every man who feels that he is ready to perish and that he cannot save himself. We believe in the Lord Jesus, and we have eternal life.
C.H. Spurgeon, Faith’s Checkbook