Judges 13:16
And the angel of the LORD said unto Manoah, Though thou detain me, I will not eat of thy bread: and if thou wilt offer a burnt offering, thou must offer it unto the LORD. For Manoah knew not that he was an angel of the LORD. And the angel of the LORD said unto Manoah, Though thou detain me, I will not eat of thy bread: and if thou wilt offer a burnt offering, thou must offer it unto the LORD. For Manoah knew not that he was an angel of the LORD.
The words belong to the outset of Samson's life, when God had appointed him to accomplish a great work for Israel. For that purpose he was surrounded from birth with the most favorable conditions for physical strength, intellectual vigor, and moral purity. The utmost care was taken to secure those advantages because of the work he was designed to do.
The refusal to eat and the direction to offer only to the Lord show that God communicates with human beings through angels. The appearance to Manoah is an example of an angel sent as a messenger. His presence and instruction illustrate that angelic office of bearing God's communication to men.