Because God ordained it in Scripture:

“Pray for the peace of Jerusalem…” Psalm 122:6a

Because God will bless those who do:

“And I will bless those who bless you, And the one who curses you I will curse.” Genesis 12:3a; Psalm 122:6b

Because God gave us the Scriptures, the covenants, the promises and Jesus Christ through Israel:

“[W]ho are Israelites, to whom belongs the adoption as sons, and the glory and the covenants and the giving of the Law and the temple service and the promises, whose are  the fathers, and from whom is the Christ according to the flesh, who is over all, God blessed forever. Amen.” Romans 9:4-5

Because the Apostle Paul prayed for Israel:

“Brethren, my heart’s desire and prayer to God for them is for their salvation.”
Romans 10:1

Because Israel, individually and as a nation, needs to be saved:

“…A partial hardening has happened to Israel until the fullness of the Gentiles has come in; and so all Israel will be saved; just as it is written, ‘The Deliverer will come from Zion, He will remove ungodliness from Jacob.’” Romans 11:25b-26

Because, as the Church fulfills her mission, she must not forget the Jews and Israel:

“For I am not ashamed of the gospel, for it is the power of God for salvation to everyone who believes, to the Jew first and also to the Greek.” Romans 1:16

Because, by praying for Israel, you will be part of God’s end-time plan:

“This gospel of the kingdom shall be preached in the whole world as a testimony to all the nations, and then the end will come.” Matthew 24:14; Revelation 7:4