Incense was offered twice a day, morning and evening, on the incense altar (also known as the golden altar or inner altar). The incense represented the worship of the heart, which is what prayer is all about. As we read, “Take my prayer as an offering of incense” (Psalms 141:2).
The burning of incense also represented another fundamental value, namely repentance. When we repent, we “burn up” our sins and cling to God, ascending higher and higher like the incense smoke.