Sforno on Exodus 30:1/ספורנו על שמות ל׳:א׳

1מזבח מקטר קטורת, he will put only a minimal amount of fire on that altar in order to burn the incense thereon. This altar did not have to be hollow, filled with earth, as was the copper altar which was filled with earth in order that the supply of fire be on the earth, literally. On this altar the fire was kept on the gold overlay. Seeing that there was only a minimal amount of fire kept going thereon this did not damage or burn wood underneath the gold overlay. The reason that this altar has not been mentioned together with the major altar standing outside the sanctuary, details of which the Torah described in Parshat Terumah, is that this altar was not intended to ensure that the Shechinah made its permanent home among the Jewish people. The purpose of all the other furnishings in the Tabernacle was just that. (compare how G’d defined this purpose in Exodus 25,8-9) Its purpose was also not to attract the glory of the Lord into the Tabernacle, as was the purpose of all the other communal sacrifices burnt-offering, gift offerings, etc. Concerning G’d’s response to those offerings we had read in Exodus 29,43 ונועדתי שמה לבני ישראל, “and there I will meet with the Children of Israel.” Moses himself had confirmed that this was the purpose of the furnishings, etc., in the Tabernacle when he said: (Leviticus 9,6) “and as a result the glory of the Lord will become manifest to you.” The sole purpose of the golden altar was to honour G’d after He had accepted our service with goodwill mornings and evenings. We used this as a means to welcome His presence by presenting the incense. We find that Chronicles I 16,29 expresses this thought, David saying:הבו לה' כבוד שמו ובאו לפניו, “Ascribe to the Lord the glory of His name!”