This verse anticipates the kingship in Judah (compare 17:6, 16; 35:11). Although Joseph received the birthright blessing, Judah would provide Israel's rulers (see 1 Chronicles 5:1–2). Many kings from Judah would hold the scepter, the symbol of rule. The final king would be the one to whom the scepter belongs, the promised Messiah (see 2 Samuel 7:4–16; Psalms 2, 45, 60; Isaiah 11; Ezekiel 21:26–27; Zechariah 9:9; Revelation 5:5).
from between his feet: This is a poetic way to refer to reproductive organs.
until Shiloh comes and the allegiance of the nations is his: This wording reflects a long-standing way of understanding a difficult Hebrew phrase. Other translations include until the coming of the one to whom it belongs or until tribute is brought to him and the peoples obey.
The right to rule Israel belongs to Judah’s descendant through David’s line (2 Samuel 7:8–16). He will eventually rule all nations, as shown by the bringing of tribute (see Psalms 68:29; 72:8–11; Isaiah 2:2–4; Ephesians 4:8–10).