The Gospel of Luke teach to us the Beatitudes in Luke 6: 20-23; the commandment of love in Luke 10:27; the importance of acquiring wisdom, listening to the word, Luke 11:28.
Then the Gospel of Luke summarizes: "But seek his kingdom, and thse things will be given to you as well", Luke 12:31.
Kingdom of God in the Bible means dominion, empire, kingdom of the divine perfections: dominion of the council, dominion of perseverance, dominion of the peace.
The gifts are perfections, excellences. A perfection is what can not be surpassed in its genre. For example in the genre of love we have: Eros, love of lovers, Philia, love of the Friends, and Agape the love for God. The Agape or Love of Charity is a perfection, a gift.
The Kingdom of God is the permanent pursuit of the excellence, in that consist  the Beatitudes, the commandment of love and the listening. The Gospel of Luke speaks to us of a trusting surrender, of a security in the Kingdom, based on knowledge and not in a simple faith. There is, in this search for the kingdom of God in the Gospel of Luke an allusion to the Security in God and in the Providence, from the point of view of the theology.
The kingdom of God has to do with the hit and the error (heresy). We  target or we fail.
True or false, correct or wrong. And on this the Law of the Return acts, "you reap what you sow" Galatians 6:7.
The law of return acts upon our gifts and sins, as is written in the beatitudes and curses of the Gospel of Luke.
In the beatitudes for those who live according to God's law are preset a series of blessings. And on the other side curse to those who sin.
Seek the Kingdom of God is to search the eternal life, to achieve the conformity to God, to emulate him. Happiness is not an end, so the scholastics authors speak about the opinated happiness, happiness is a return. True happiness, the happiness of the heart, is a gift of God, an aspect of the eternal life. The purpose of spiritual life is the permanent perfectioning. That is the goal of the truly intelligent.