The incense was conditioned to be ‘sweet incense’. The Lord says: “Aaron shall burn on it sweet incense every morning” (Ex.30: 7). And also at twilight “he shall burn incense on it, a perpetual incense before the Lord throughout your generations” (Ex.30: 8).
The spices for making the sweet incense are mentioned in (Ex.30: 34). It is said that this incense “shall be to you holy for the Lord” (Ex.30: 37). Moreover, “It shall be most holy to you... you shall not make any for yourselves, according to its composition” (Ex.30: 36,37).
The phrase ‘sweet incense’ is repeated on many occasions in the Holy Bible: (Ex.25: 6); (Ex.37: 29); (Lev.16: 12). So incense represented a fragrant perfume ascending before the Lord.