Repetitions have diverse uses in Scripture.
In prayer they argue affection.
In prophecy they note celerity and certainty.
In threatenings they note unavoidableness and suddenness
In precepts they note a necessity of performing them.
In truths, like that before us, they serve to show the necessity of believing and knowing them.
J. C. Ryle, Expository Thoughts on the Gospel of John, Vol. 1 (pg. 7).
Repentance and faith are the gifts of God, and gifts that he often withholds, when they have been long offered in vain. I grant you true repentance is never too late, but I warn you at the same time, late repentance is seldom true. I grant you, one penitent thief was converted in his last hours, that no man might despair; but I warn you, only one was converted, that no man might presume….
It was said of a famous general of old, when he could have taken the city he warred against, he would not, and by and by when he would, he could not. Beware, lest the same kind of event befall you in the matter of eternal life.
J. C. Ryle, Thoughts for Young Men (pg. 10).