Midrasch zu Schemuel II 6:13

(II Sam. 6, 13) And it happened that, when the bearers of the ark of the Lord had progressed six paces, he sacrificed an ox and a failing, and again it is written concerning the same (I Chr. 15, 26) That they offered seven bullocks and seven rams. How are both passages to be reconciled? Saul R. Papa b. Samuel: "On each and every pace, they slaughtered an ox and a fatling and on every six paces they sacrificed seven oxen and seven fatlings." "Whereupon R. Chisda said to him: "According to this then the entire land of Israel must have been turned into a sacrificing altars?" R. Chisda therefore said: "This means that on every six rounds of six paces they sacrificed seven bullocks and seven rams." It is written (Ib. 13, 9) The threshing floor of Kidon, and again it is written concerning the same (II Sam. 6, 6) The threshing floor of Nachon. How are both of these names to be reconciled? Said R. Jochanan: "In the beginning it was called Kidom (a spear) and finally [after it had been kept in the house of Obod Edom], it was called Nachon [preparing place, for that place prepared the ark to be taken over into the tabernacle which David constructed for it].