This verse of Matthew is similar to Luke, chapters 9:48 and 10:16, Mark, chapter 9:37, and John 12:44. Quite often the idea is associated with accepting children. Here it is Jesus himself. Whoever accepts, welcomes, or receives his followers or disciples (Ὁ δεχόμενος ὑμᾶς), then they would be accepting Jesus (ἐμὲ δέχεται). Furthermore, if they are welcoming Jesus (καὶ ὁ ἐμὲ δεχόμενος), then they are receiving, accepting, and welcoming the one who sent Jesus (δέχεται τὸν ἀποστείλαντά με), the Father. There is a clear connection between God, the Father, Jesus, and his followers. Accepting one means accepting all.
This saying of Jesus is exactly the same as in Luke, chapter 11:9-10, indicating a common Q source. Jesus told them to ask (Αἰτεῖτε), and they would get it (καὶ δοθήσεται ὑμῖν). Seek (ζητεῖτε), and they would find (καὶ εὑρήσετε). Knock (κρούετε), and it will be opened (καὶ ἀνοιγήσεται ὑμῖν). Everyone who asked would receive (πᾶς γὰρ ὁ αἰτῶν λαμβάνει) what he asked for. The seeker will find (καὶ ὁ ζητῶν εὑρίσκει) what he is looking for. The one knocking will see it open (καὶ τῷ κρούοντι ἀνοιγήσεται). All is well that ends well. You just need a little effort.
As in the preceding chapter, King Zedekiah (598-587 BCE) has confined Jeremiah to the royal prison. Here, Jeremiah receives a second oracle from Yahweh. Like the preceding chapter, this is a different numbered chapter in the Greek translation of the Septuagint, chapter 40, not chapter 33 as here.