You cant believe that and insist the 144 000 in Rev 7 is confined to ethnic jews, and doesnt include all nations, tongues as in Vs 9-10
9 After this I beheld, and, lo, a great multitude, which no man could number, of all nations, and kindreds, and people, and tongues, stood before the throne, and before the Lamb, clothed with white robes, and palms in their hands;
10 And cried with a loud voice, saying, Salvation to our God which sitteth upon the throne, and unto the Lamb.
These verses are the interpretation of exactly who the 144 000 are ! Its the fulfillment of Gods Promise to Abraham here Gen 15:4-6
4 And, behold, the word of the Lord came unto him, saying, This shall not be thine heir; but he that shall come forth out of thine own bowels shall be thine heir.
5 And he brought him forth abroad, and said, Look now toward heaven, and tell the stars, if thou be able to number them: and he said unto him, So shall thy seed be.
6 And he believed in the Lord; and he counted it to him for righteousness.