The Lenten Triodion, starting point for Easter - warnings against pride and hypocrisy

Written for the devout Christian, the Triodion is full of warnings against pride and hypocrisy - the ultimate spiritual sins to which religious folk are so susceptible. Its hymns teach us the true nature and purpose of fasting and of Lent itself.

(from here)

Orthodoxwiki

Parable of the Publican & Pharisee

The Lenten Triodion is the service book of the Orthodox Church that provides the texts for the divine services for the pre-Lenten weeks of preparation, Great Lent, and Holy Week. The Lenten Triodion is the title of a classic and popular English book translated with an extensive and helpful introduction by Metropolitan Kallistos and Mother Mary; it provides many (but not all) of the texts necessary to observe the great fast. In Greek and Slavonic it is simply called the triodion. It is called the triodion because the canons appointed for Matins during this period are composed of three odes each.
The weeks of preparation, and especially the Sunday gospel readings, serve to exercise the mind, whereas the fasting of Great Lent focuses on the body, and Holy Week's services exercise the spirit.

Weeks of preparation 

The three weeks that commence on the fourth Sunday prior to Great Lent constitute the weeks of preparation. Each has its own distinct theme which is expressed in the Gospels readings appointed for the Divine Liturgies on these days:

Sunday of the Prodigal Son

1. Sunday of the Publican and Pharisee (Luke 18:9-14),

2. Sunday of the Prodigal Son (Luke 15:11-32), and

3. Sunday of the Last Judgment (also called Meatfare Sunday; Matt 25:31-46).

4. Sunday of Forgiveness (also called Cheesefare Sunday; the expulsion of Adam from Eden is also a theme of this day); Matt 6:14-21.

The Church eases us into the Lenten fasting discipline during this period. The week following the Sunday of the Publican and Pharisee is fast-free. The week following the Prodigal Son is a normal week -- we fast as usual on Wednesday and Friday. In the week following Meatfare Sunday, no meat is eaten; eggs, fish, and dairy are permitted on any day.
Forgiveness Sunday brings the period of preparation to an end. The next day, Clean Monday, begins Great Lent. The Vespers service served on the evening of Forgiveness Sunday includes the Rite of Mutual Forgiveness and is the first service of Great Lent.

Great Lent

Jesus Christ the Bridegroom (Holy Week)

Great Lent begins on the Monday following Forgiveness Sunday (also called Cheesefare Sunday) with each Sunday highlighted as follows:

1. Sunday of Orthodoxy (John 1:43-51),

2. Sunday of St. Gregory Palamas,

3. Sunday of the Holy Cross,

4. Sunday of St. John Climacus, and

5. Sunday of St. Mary of Egypt.

Holy Week

Great Lent is followed by Holy Week, the week beginning with Palm Sunday and preceding Pascha. 

Click:

Triodion resource page