Charles H. Spurgeon on Psalms 141:2

As incense. That in general by incense prayer is signified, the Scripture expressly testifieth. And there is a fourfold resemblance between them:

1. In that it was beaten and pounded before it was used. So doth acceptable prayer proceed from a broken and contrite heart: Ps 51:17.

2. It was of no use until fire was put under it, and that taken from the altar. Nor is that prayer of any virtue or efficacy which is no kindled by the fire from above, the Holy Spirit of God, which we have from our altar, Christ Jesus.

3. It naturally ascended upwards towards heaven, as all offerings in the Hebrew are called twle, "ascensions", uprisings. And this is the design of prayer, to ascend unto the throne of God: "I will direct unto thee, and will look up"; that is, pray: Ps 5:3.

4. It yielded a sweet savour; which was one end of it in temple services, wherein there was so much burning of flesh and blood. So doth prayer yield a sweet savour unto God; a savour of rest, wherein he is well pleased. —John Owen.