Another parable He put forth to them, saying: “The kingdom of heaven is like a mustard seed, which a man took and sowed in his field, which indeed is the least of all the seeds; but when it is grown it is greater than the herbs and becomes a tree, so that the birds of the air come and nest in its branches.”
— Matthew 13:31-32

By the Holy Spirit Jesus always testified of Himself, or of the truth, and the truth is in Jesus. So all the parables reveal the glory of Jesus Christ and the power of His finished work. The mustard seed is the seed of faith. [Mat.17:20] Jesus is our faith [Jesus Is Our Faith and Our Strength]. Jesus is also the grain, the manna from heaven, which came down from heaven to earth. [Manna, or the Grain of Heaven] The sower is the Son of Man, who gave Himself as a sacrifice on the cross. [Heb.7:27] The tree is the end result of the seed — His finished work on the cross. The birds are the evil one, the serpent, whose image the Son of Man took on the cross. [Jhn.3:14]

Another parable He spoke to them: “The kingdom of heaven is like leaven, which a woman took and hid in three measures of meal till it was all leavened.”
— Matthew 13:33

The woman is the grace of God, for Sarah, a type of grace, kneaded three measures of meal and made cakes. [Gen.18:6] The three measures of meal are our beloved Lord Jesus Christ, in whom dwells all the fullness of the Godhead bodily — the Father, the Son and the Holy Spirit [Col.2:9] The Son of Man is grace itself, for grace and truth came through Jesus Christ. [Jhn.1:17] The leaven is sin, malice and wickedness. [1 Cor.5:8] There, in Genesis, Sarah kneaded the dough without leaven, for our Lord was born without sin. On the cross Jesus became sin [was completely leavened], so that in Him we would forever become the righteousness of God [2 Cor.5:21]