Psalms 122:4 - Matthew Poole's English Annotations on the Holy Bible

The tribes; not some few pious people of each tribe, as in Saul's time and under the judges, but whole tribes; nor only one or two of the tribes, as it was during the late civil wars, but all the twelve tribes. The tribes of the Lord; whom God hath chosen to be his people, and whom he hath invited and required to resort thither. Unto the testimony of Israel; unto the ark, which is oft called the testimony, as Exodus 16:34 Leviticus 16:13, Leviticus 24:3 Num 17:, 1, and more fully the ark of the testimony, as Exodus 26:33,34, and elsewhere; because of the tables of the covenant laid up in it, which are called God's testimony, and the tables of the testimony, as Exodus 25:16, Exodus 31:18, &c. And this may well be called the testimony of or to Israel, because it was given by God to them and for their good. Or, by or according to the testimony of Israel, i.e. God's command given to Israel, which may be alleged here as the reason which moved them to this journey. To give thanks unto the name of the Lord; to worship God; this one eminent part and action thereof being put for all the rest.