Commentary for Psalms 16:5

The Lord is my allotted portion and my cup All my benefit is from Him. Another explanation: כוסי means “my share,” as (in Exod. 12:4): “you shall make your count (תכסו) on the lamb.” This is how Menachem (p. 107) associated it.

The Lord is the portion of mine inheritance and my cup: – I have no other portion beside Him as these men have, whose inheritance and portion is silver and gold and the pleasures of the world; but, as for me, the Lord is the portion of mine inheritance and my cup. The portion, the inheritance, the cup, and the lot are identical; it is simply a repetition of the idea with a change of terms to give emphasis, as is the custom of the language; the meaning being, in all my words and in all my affairs He is my inheritance and to Him is my devotion (directed). And the interpretation of

You guide my destiny It is You Who placed my hand on the good share, as it is stated (in Deut. 30:19): “I have set life and death before you...Choose life...” as a man who loves one of his sons and lays his hand on the better share, saying, “Choose this one for yourself.”