Insert cell data every given amount of rows

I got one column with data.
I want to insert a cell with text for a certain amount of rows in that
column.
How can I do that?

Example with text for each 4 rows:

From
1
2
3
4
5
6
7
8
9

to
1
2
3
4
TEXT
5
6
7
8
TEXT
9


Regards
Mike