What does Matthew 15:24 mean?
He answered, “I was sent only to the lost sheep of the house of Israel.”
The question we received was why was the seeker turned away (temporarily) and why did Jesus say he was “only” seeking the “lost sheep of Israel.” Did he not care for the others? There is an earlier related passage.
These twelve Jesus sent out, instructing them, “Go nowhere among the Gentiles and enter no town of the Samaritans,  but go rather to the lost sheep of the house of Israel.
I. R. T. France, Matthew, P. 177,178
Re: Mt 10:5,6:
“This startling restriction of the disciples’ mission to Israel is found only in Matthew, where it is matched by an equally restricted statement of Jesus’ own mission (15:24). Yet this same Gospel not only recognizes a deliberate mission to Gentiles at a later period, after the resurrection (28:19-10; 24:14), but also includes sayings of Jesus which include other nations in God’s plan of salvation (8:11,2; 21:43; 25:32), and we have seen in the early chapters a clear interest in the significance of Jesus for the Gentiles (2:1-12; 4:14-16, 24-25). Matthew cannot then be accused of anti-Gentile bias. Rather this saying reflects the historic fact that with very few exceptions (8:5-13 deals with a Gentile in Jewish territory; 15:21-28 is clearly presented as exceptional) the mission of both Jesus and his disciples before the resurrection was in fact limited to Israel; the time for the Gentile mission was later. The emphasis of the saying lies not primarily in the prohibition of a wider mission, but on the primary focus of Jesus’ ministry; the call was urgent and demanded total concentration (cf. 10:23). They were lost sheep, a common Old Testament metaphor (Jer 50:6; Ezk 34:1-16; Is 53:6)…”
II. Other notes.
The original Greek reads something like
“I was not sent except to the lost sheep of the house of Israel”
“I am not sent but unto the lost sheep of the house of Israel.” King James Version
That puts the emphasis on Jesus following his calling to Israel. See Mark 1:35-39 for the sense that Jesus ministry was directed by the Father; John 2:4 for the importance of timing, and John 17:4 for the importance of Jesus doing what the Father directed.