Grammatically Correct: The writer's essential guide to punctuation ...

PUNCTUATION
reconcile the last sentence with its predecessor: The relationship
will have been anticipated.
Consider the next example:
Profiles are text commands that contain commands. You can edit them,
but always keep a backup. If you change them incorrectly, the behavior
of the editor may be affected.
Profiles are text commands that contain commands. You can edit them,
but always keep a backup: If you change them incorrectly, the behavior
of the editor may be affected.
In version A, the reader might see the three sentences as three
independent items of information, and fail to pick up on the critical
connection between the last two. In version B, the colon alerts the
reader to the fact that there is a particular reason for keeping a
backup copy, and that this reason is about to be explained.
Similarly,
Voters approved the controversial amendment by an extremely narrow
margin. The count was 18,278 in favor and 17,916 against.
Voters approved the controversial amendment by an extremely narrow
margin: 18,278 in favor and 1 7,916 against.
In version A, the reader must expend a bit of extra energy figuring
out that the purpose of the figures given in the second sentence is
to illustrate the narrowness of the margin. In version B, the structure
makes this connection instantly obvious.
RECOMMENDATION: USE A COLON TO ADD EMPHASIS
Judicious use of the colon can serve to make a point more emphatic.
If your intention is to draw a contrast between two elements, this
contrast may come through more forcefully if the elements are
in immediate juxtaposition, rather than being placed in different
sentences or separated by intervening text.
Compare the two passages below:
The next witness testified that she had been fired from her job as a line
supervisor. Her offense was that she had tried to organize the factory's
200 workers, who earned an average of $90 a week.
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