Moses
Exodus 19:1ESV·traditional attribution

On the third new moon after the people of Israel had gone out of the land of Egypt, on that day they came into the wilderness of Sinai.

John Calvin Reformed @genevareformer

1. In the third month. This chapter informs us by what means God rendered the people attentive and teachable when He would promulgate His laws. He had, indeed, previously delivered the rule of a just and pious life, but by writing the Law on tables, and by then adding its exposition, He not only embraced the perfect doctrine of piety and righteousness, but ratified it...

Matthew Henry Presbyterian @wholebiblehenry

Here is, I. The date of that great charter by which Israel was incorporated. 1. The time when it bears date (Exo 19:1) - in the third month after they came out of Egypt. It is computed that the law was given just fifty days after their coming out of Egypt, in remembrance of which the feast of Pentecost was observed the fiftieth day after...

Commenting on Exodus 19:1-8

John Gill Reformed Baptist @doctorgill

In the third month, when the children of Israel were gone forth out of the land of Egypt,.... Which was the month Sivan, and answers to part of May and part of June: the same day came they into the wilderness of Sinai; which had its name from the mountain situated in it, and that from the bushes which grew upon it.