This Generation 
At first look, there seems to be a contradiction in Psalm 89. 
For the LORD is our defence; and the Holy One of Israel is our king. ¶ Then thou spakest in vision to thy holy one, and saidst, I have laid help upon one that is mighty; I have exalted one chosen out of the people. I have found David my servant; with my holy oil have I anointed him: With whom my hand shall be established: mine arm also shall strengthen him. The enemy shall not exact upon him; nor the son of wickedness afflict him. And I will beat down his foes before his face, and plague them that hate him. But my faithfulness and my mercy shall be with him: and in my name shall his horn be exalted. I will set his hand also in the sea, and his right hand in the rivers. He shall cry unto me, Thou art my father, my God, and the rock of my salvation. Also I will make him my firstborn, higher than the kings of the earth. My mercy will I keep for him for evermore, and my covenant shall stand fast with him. His seed also will I make to endure for ever, and his throne as the days of heaven. If his children forsake my law, and walk not in my judgments; If they break my statutes, and keep not my commandments; Then will I visit their transgression with the rod, and their iniquity with stripes. Nevertheless my lovingkindness will I not utterly take from him, nor suffer my faithfulness to fail. My covenant will I not break, nor alter the thing that is gone out of my lips. Once have I sworn by my holiness that I will not lie unto David. His seed shall endure for ever, and his throne as the sun before me. It shall be established for ever as the moon, and as a faithful witness in heaven. Selah. 
(Psalms 89:18-37)
There are also elements of the promise of Messiah here, not so? 
But thou hast cast off and abhorred, thou hast been wroth with thine anointed. Thou hast made void the covenant of thy servant: thou hast profaned his crown by casting it to the ground. Thou hast broken down all his hedges; thou hast brought his strong holds to ruin. All that pass by the way spoil him: he is a reproach to his neighbours. Thou hast set up the right hand of his adversaries; thou hast made all his enemies to rejoice. Thou hast also turned the edge of his sword, and hast not made him to stand in the battle. Thou hast made his glory to cease, and cast his throne down to the ground. The days of his youth hast thou shortened: thou hast covered him with shame. Selah. How long, LORD? wilt thou hide thyself for ever? shall thy wrath burn like fire? Remember how short my time is: wherefore hast thou made all men in vain? What man is he that liveth, and shall not see death? shall he deliver his soul from the hand of the grave? Selah. Lord, where are thy former lovingkindnesses, which thou swarest unto David in thy truth? Remember, Lord, the reproach of thy servants; how I do bear in my bosom the reproach of all the mighty people; Wherewith thine enemies have reproached, O LORD; wherewith they have reproached the footsteps of thine anointed. Blessed be the LORD for evermore. Amen, and Amen. 
(Psalms 89:38-52)
This Psalm was written by Ethan the Ezrahite, who was regarded as a wise man in the time of Solomon (see 1 Kings 4:31). 
We can deduce therefore that even in the time of Solomon - one generation away from David the king - there was much disobedience and rebellion to the will of God. 
If we look at Exodus we shall see that God offered to make a Covenant with the nation of the Children of Israel (the Jews) and that the people agreed to the terms of the Covenant: 
And Moses went up unto God, and the LORD called unto him out of the mountain, saying, Thus shalt thou say to the house of Jacob, and tell the children of Israel; Ye have seen what I did unto the Egyptians, and how I bare you on eagles' wings, and brought you unto myself. Now therefore, if ye will obey my voice indeed, and keep my covenant, then ye shall be a peculiar treasure unto me above all people: for all the earth is mine: And ye shall be unto me a kingdom of priests, and an holy nation. These are the words which thou shalt speak unto the children of Israel. And Moses came and called for the elders of the people, and laid before their faces all these words which the LORD commanded him. And all the people answered together, and said, All that the LORD hath spoken we will do. And Moses returned the words of the people unto the LORD. ¶ And the LORD said unto Moses, Lo, I come unto thee in a thick cloud, that the people may hear when I speak with thee, and believe thee for ever. And Moses told the words of the people unto the LORD. And the LORD said unto Moses, Go unto the people, and sanctify them to day and to morrow, and let them wash their clothes, And be ready against the third day: for the third day the LORD will come down in the sight of all the people upon mount Sinai. 
(Exodus 19:3-11)
We also remember that God wanted to make the Covenant void because of disobedience, but listened to the pleading of Moses. 
To this day, the Jews believe in the everlasting Covenant that God made with them: 
*A Psalm.* O sing unto the LORD a new song; for he hath done marvellous things: his right hand, and his holy arm, hath gotten him the victory. The LORD hath made known his salvation: his righteousness hath he openly shewed in the sight of the heathen. He hath remembered his mercy and his truth toward the house of Israel: all the ends of the earth have seen the salvation of our God. 
(Psalms 98:1-3)
Going to the state of Israel today, it's apparent that the Founding Statement is not Biblically true. The first sentence states: "Eretz Yisrael was the birthplace of the Jewish people."; nor is God honoured as their Covenant Partner and Protector as He should be. This is why they are having the fighting that there is. Remember, God gave them the land and they were unbeatable while being obedient to Him. 
Who will bring me into the strong city? who will lead me into Edom? Wilt not thou, O God, who hast cast us off? and wilt not thou, O God, go forth with our hosts? Give us help from trouble: for vain is the help of man. Through God we shall do valiantly: for he it is that shall tread down our enemies. 
(Psalms 108:10-13)
(Edom - the children of Esau, some of who the Jews are fighting today) 
However, if we consider the supernatural wonders of the six day war it becomes apparent that God still honours the Covenant that He made with that nation. 
O give thanks unto the LORD; call upon his name: make known his deeds among the people. Sing unto him, sing psalms unto him: talk ye of all his wondrous works. Glory ye in his holy name: let the heart of them rejoice that seek the LORD. Seek the LORD, and his strength: seek his face evermore. Remember his marvellous works that he hath done; his wonders, and the judgments of his mouth; 
(Psalms 105:1-5)
Thus were they defiled with their own works, and went a whoring with their own inventions. Therefore was the wrath of the LORD kindled against his people, insomuch that he abhorred his own inheritance. And he gave them into the hand of the heathen; and they that hated them ruled over them. Their enemies also oppressed them, and they were brought into subjection under their hand. Many times did he deliver them; but they provoked him with their counsel, and were brought low for their iniquity. Nevertheless he regarded their affliction, when he heard their cry: And he remembered for them his covenant, and repented according to the multitude of his mercies. 
(Psalms 106:39-45)
Placed in the perspective of the time of Jesus of Nazareth's public ministry, which ministry confirmed the Covenant that God made with the nation - the ministry of the Messiah to the "lost sheep of the house of Israel", He called many of the elders and chief priests "this generation" or "a generation of vipers", because most were personally disobedient to the undertaking that their forefathers had made in the shadow of the mountain and as a result could not "know" that He was the Messiah even though it was generally accepted or hoped that He was by the common people. 
And, behold, two blind men sitting by the way side, when they heard that Jesus passed by, cried out, saying, Have mercy on us, O Lord, thou Son of David. And the multitude rebuked them, because they should hold their peace: but they cried the more, saying, Have mercy on us, O Lord, thou Son of David. And Jesus stood still, and called them, and said, What will ye that I shall do unto you? They say unto him, Lord, that our eyes may be opened. So Jesus had compassion on them, and touched their eyes: and immediately their eyes received sight, and they followed him. 
(Matthew 20:30-34)
And when they drew nigh unto Jerusalem, and were come to Bethphage, unto the mount of Olives, then sent Jesus two disciples, Saying unto them, Go into the village over against you, and straightway ye shall find an ass tied, and a colt with her: loose them, and bring them unto me. And if any man say ought unto you, ye shall say, The Lord hath need of them; and straightway he will send them. All this was done, that it might be fulfilled which was spoken by the prophet, saying, Tell ye the daughter of Sion, Behold, thy King cometh unto thee, meek, and sitting upon an ass, and a colt the foal of an ass. And the disciples went, and did as Jesus commanded them, And brought the ass, and the colt, and put on them their clothes, and they set him thereon. And a very great multitude spread their garments in the way; others cut down branches from the trees, and strawed them in the way. And the multitudes that went before, and that followed, cried, saying, Hosanna to the Son of David: Blessed is he that cometh in the name of the Lord; Hosanna in the highest. 
(Matthew 21:1-9)
(Hosanna to the Son of David - save us Son of David[Messiah]) 
Bearing then the preceding examples of God's promises in mind as it concerns the "church", we see from the parable of the sower (Mt 13:1-9) that the four kinds of seed were all from the multitudes who came to listen. The uninterested weren't there. Likewise in the parable of the pounds (Lu 19:11-27) there were some who weren't prepared to let Him rule over them. In the teaching of the strait* gate and narrow way (Mt 7:13; Lu 13:24) it also concerns those who are in "the way" - the church; those who came to listen. 
In the above parables as well as in Ephesians (the letter to the church of Jesus Christ): 
For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: Not of works, lest any man should boast. For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them. 
(Ephesians 2:8-10)
we see that being "saved" is coming into Covenant with God, but that thereafter our works should be those of obedience to God's will. James 2:20-24 confirms this. 
That in the ages to come he might shew the exceeding riches of his grace in his kindness toward us through Christ Jesus. 
(Ephesians 2:7)
*meaning a narrow entrance full of obstacles, anguish or distress. Something different from mere narrowness - something that needs determination to pass through.