John Wesley on Psalms 68:27

There is - Present in this solemn pomp of carrying the ark to Zion. Little - Called little, because it was exceedingly diminished, and almost extinguished under the Judges, Judg 20:35 21:3 &c. Ruler - The tribe which had lately swayed the scepter, but now submitted to David. Company - The people of that tribe who waited upon them. Zebulun, &c. - He mentions these tribes, because they lived in the remotest parts of the land of Canaan. And so by naming two of the nearest tribes, and two of the farthest, he intimates that the other tribes also came upon this occasion, as is manifest from 2Sam 6:15 - 19.