Thou shalt... put it before the testimony. — Some pieces of the incense were to be continually before the ark of the covenant, either on the golden altar, or perhaps at its base ready for offering. This would symbolise the need of the perpetual offering of prayer.
Related Commentaries of Exodus 30:36
Exodus 30:36
36 And thou shalt beat some of it very small, and put of it before the testimony in the tabernacle of the congregation, where I will meet with thee: it shall be unto you most holy.