How do you know disobeyed the god ?

Answer 1

Deep within his conscience man discovers a law which he has not laid upon himself but which he must obey.

Its voice, ever calling him to love and to do what is good and to avoid evil, sounds in his heart at the right moment.

For man has in his heart a law inscribed by God.

His conscience is man's most secret core and his sanctuary.

There he is alone with God whose voice echoes in his depths.

With love in Christ.

Answer 2

Some things like adultery and murder are pretty straightforward. Other things are less straightforward and you may not remember being unkind to someone for example.

So I pray and ask God to reveal my sins to me. God generously answers prayers like that. Here is an example prayer.

O God, Father of Light, who enlightenest everyone that comes into this world, give me light, love and sorrow, that I may discover, detest, and confess all the sins I have committed.

O Holy Spirit, Spirit of Love and Dispenser of all grace, help me to receive this great Sacrament worthily; give me Thy grace that I may make a careful examination of conscience and discover my sins; touch my heart that I may hate and detest them, and assist me to make a firm resolution to avoid sin henceforth. Spirit of Love and Truth, assist me to make a sincere, entire and truthful Confession to the Representative, the priest, and thus obtain Thy forgiveness, Thy grace and Thy love.

O Jesus, my Redeemer, through Thy most holy merits, grant me the grace of heartfelt contrition and amendment of life. To Thee I look for the grace to make this Confession well, that I may glorify Thee.

O most holy Virgin Mary, Mother of my Savior, and my own most loving Mother, thou who art so compassionate towards those who desire to repent, help me to call to mind all my offenses and to be truly sorry for having offended God.

My dear Guardian Angel, who hast been a witness of my sins, help me now to recall them and to be truly sorry for them. All you Saint and Angels of Heaven, pray for me that I may now bring forth fruits worthy of penance.