whatever you bind on earth ... This language refers to decisions made about who is in and out of the faithful group of disciples. Jesus was claiming to have authority to determine who the people of God are based on whether they follow his instructions. See also 16:19.
If two agree – Matthew 18:19
If two of you agree. This is not a universal statement about the power of two people agreeing with each other, but in context Jesus was talking about the authority of his disciples as the gathered people of God.
The Parable of the Unforgiving Servant - Matthew 18:21-35
This lengthy and important parable highlights the major theme in Matthew of the importance of showing mercy and forgiving each other (Matt. 1:19; 5:7; 6:12-15; 9:13; 12:7). See WLC 194; WSC 105; BC 31: HC 105, 126.
Seven times seventy – Matthew 18:21-22
Seven times ... seventy times seven. Forgiving someone who has wronged you seven times would be a commendable virtue. But Jesus said "seventy times seven" which is a dramatic way of saying that our forgiveness of others should be unlimited in number.
A talent – Matthew 18:24
Talent. In current weight this would be about 75 pounds or 34 kilograms.
Servitude – Matthew 18:25
Commanded him to be sold. In the ancient world people and their families could often be sold into servitude until their debts were paid.
Jesus on Divorce and Remarriage - Matthew 19:3-12
The difficulties of marriage, divorce, and remarriage are universal. As an influential teacher in his day Jesus was asked about his views on these moral matters. His answer was very conservative, but focuses on the heart issues and God's design for human union rather than on all the details of when divorce is right or wrong. Jesus ended his teaching with a call to discipleship, to trusting in his wisdom, even if that means to remarrying after a wrongful divorce (becoming a "eunuch for the kingdom"). Jesus also included the same comments on divorce and remarriage in the Sermon on the Mount (Matt. 5:31-32).
Hardness of heart – Matthew 19:8
Hardness of heart. Repeatedly, Jesus emphasized the importance of the inner person or heart, not just outward actions Matt. (5:8, 21-48; 6:21; 15:7-11; 22:37).
Eunuchs – Matthew 19:12
Eunuchs for the sake of the kingdom. Jesus was not referring here to physical eunuchs, nor encouraging people to mutilate themselves. Rather, these people are those who choose not to remarry in obedience to Jesus if they have been involved in a wrongful divorce, because remarriage after a wrongful divorce is declared to be adultery (Matt. 5:31-32).
Such ones - Matthew 19:14
The kingdom of heaven belongs to such ones. Jesus used children as a model for kingdom of heaven disciples because of their humility and trusting faith.
Perfect - Matthew 19:21
If you wish to be perfect. The word translated "perfect" should be understood in the sense of mature, complete, or whole. It is the same word used in the Sermon on the Mount to describe the heart of the true disciple, the ones who are like their heavenly Father (Matt. 5:48). The man who came to Jesus in this story was genuinely righteous in his behavior but he lacked the greater righteousness required to enter the kingdom of heaven (Matt. 5:20) — right behavior that comes from a heart/inner person that loves God and others (Matt. 22:37-40). This man loved his possessions more than God and so lacked the whole or complete righteousness he required.