THIS verse is an overall evaluation of the general ministry of the teachers of the law and the Pharisees. This evaluation could be seen in many and different ways in the practice and teaching of these religious leaders.
God had given the Jews the law of Moses. We can read this law in the books of Leviticus, Numbers and Deuteronomy in particular. When we read this law, with its multiplicity of sacrifices, we can not fail to appreciate that God's law through Moses was very demanding. The business of the Pharisees and the teachers of the law was to teach and explain this law. However over the years the interpretation of this law had become more and more complicated, and the spirit of the law of Moses was lost in great numbers of outward regulations. Whereas the law of Moses laid emphasis on the heart being right with God, the teaching and interpretation of the law in Jesus' time laid great stress on outward actions, and had little if no regard for the condition of the heart.
The result of all this was that the Pharisees and teachers increased their own importance, and at the same time enforced the law as they interpreted it rigorously on those they taught and ministered to, specially those who had been won over to the Jewish faith from amongst the Gentiles. We have an example of such a person in Cornelius of whom we read in the Acts, and find Peter being sent to teach him the true way to God through faith in Jesus.
In the previous verse Jesus exposes the hypocritical life of the teachers of the law and the Pharisees. Jesus tells us that they did not practice what they preached. In other words, although they pressed the burden of the law on others, they themselves did not live by these laws themselves, except in outward show by which they sought the praise of others.
The fact is that the religion of law and works which the Pharisees enforced is always a religion which places burdens on people which they are not able to carry out. This has been true since the New Testament times wherever acceptance and favour with God has been taught as being earned by human efforts and human merit. The fact is that if people are really concerned for their relationship with God, and being accepted by God, they will always feel their short comings in their duty towards God, and in their works and obedience. Because they are really sincere in seeking God's acceptance, they will always be in fear and anxiety, because they will feel their sins and failings must bring upon them the rebuke and judgement of God.
The religion of works is always a religion of heavy burdens, because, like the Pharisees, advocates of meriting our acceptance with God never can tell their followers what is enough to gain God's favour, and so people seeking God by their religious and good living, and works of charity, will always feel condemned, and never know whether they are in the love of God or not.
The fact is that those who preach that it is by our own works we merit God's favour never lift a finger to help people bear the burden which meriting God's favour by our own effort brings down on people. Like the Pharisees, generally they are not concerned about the joy and peace of their followers, but only of their own authority and standing amongst them, and this position of authority is better enforced if people are always anxious about their failings and sins, and the condition of their soul.
On the other hand, even when there is a genuine desire in teachers of works to help people in their religion, the religion of works has no answer to the fears which are real because we do not know whether our works are sufficient to gain God's favour and acceptance.
The Pharisees and teachers of the law illustrate vividly the failure and evil of teaching people that through our own merit we earn God's favour. They wanted to dominate the people, and be above them. They wanted people to fear them and give them reverence, so they were not interested in any way for the peace, happiness or comfort of the people they dominated. It served their purpose better to make the burdens as heavy as possible.
The trouble with religion that preaches up works as the means of gaining God's favour usually finds its teachers more concerned with their own glory than the good of their followers. Jesus exposes this in the rest of the chapter.