The earliest text here reads “neither is there any conditions”. Two possible emendations have occurred in the history of the text: “neither is there any condition” (the first printing of the 1852 LDS edition) and “neither are there any conditions” (the 1840 edition). The last emendation undoubtedly represents the intended meaning of the original since the following text also has the plural conditions (“except the conditions which I have told you”). For further discussion of this type of disagreement, see under 1 Nephi 4:4 as well as under subject-verb agreement in volume 3.
Summary: Restore in Mosiah 4:8 the earliest reading, “neither is there any conditions”.