The LORD bless you and keep you;
the LORD make his face shine upon you and be gracious to you;
the LORD turn his face toward you and give you peace.
This section of the Bible, Numbers 6:23-27, is commonly referred to as the Priestly Blessing. Since Aaron was the first High Priest, it is also known as the Aaronic Blessing.
It is common for whomever is reciting the blessing to make their hands resemble the hebrew letter shin representing one of the hebrew words for God - Shaddai.
Articles of interest include:
Image from Google images