The Kedushas Levi explains the meaning of the word “laymor” by quoting the Gemara (Brachos 9B) that says that the words “Hashem sefasai tiftach” (Hashem, open my lips) is not considered an interruption between “geulah and tefillah” (the parts of davening that relate to the redemption and Shemonah Esrei). The Gemara explains that since the Chochomim enacted the saying of these words, it is like a “tefillah arichta” (an extension of the tefillah).
The Kedushas Levi explains that these words were not originally part of the Shemonah Esrei that was composed by the Anshei Knesses Hagedolah. However, the Chochomim later said to say them as an extension of the tefillah. These words were unnecessary during the generations of the Tannaim and Amoraim because their tefillos were certainly acceptable, so they didn’t need to daven for Hashem to open their lips and to help them pray. Later generations, however, were not on that level and they needed to start their tefillos with this introduction.
We see from this that there are two parts of tefillah. 1. The tefillah itself. 2. An introductory tefillah in which we ask for the ability to daven properly. Of course, all of Moshe Rabenu’s prayers were on the highest level, and this introduction was not needed. However, at this time he saw that his tefillos were not being accepted. Therefore, he needed this introductory prayer for his tefillos to enter Eretz Yisroel be said in the proper way for them to be accepted.
Accordingly, the pasuk is saying that he davened to Hashem “to say”, meaning that he prayed to be able to say his prayers properly. Although he didn’t usually need to do this, he saw that this was necessary this time.
