It may happen that when a person sets out to do a mitzva, he runs into obstacles. He then continues trying to do the mitzva, but the obstacles get harder to overcome. He may think to himself, I don't understand, I'm trying to do something for Hashem. Why would He keep trying to stop me? Does He not want me to do the mitzva? The answer is, for sure He wants you to do the mitzva, but He wants you to get the most out of it. The harder a person tries to do a mitzva, the greater the mitzva becomes. If it gets extremely difficult to do, and the person continues to persevere, his rewards for that mitzva will be unimaginable. The Sefer Sas V'Imratecha tells the following story, which took place a number of years ago. Two great Rebbes, who were brothers, arranged a tish on Tu B'shvat, and suddenly, at around midnight, one said to the other that they hadn't done the mitzva of Birkat HaLevana yet. This was the last night to do it, and there were only a few hours left to get it done. The problem was that it was overcast with thick clouds, and there was a very slim chance that the moon would appear in the next few hours. At that time, they were in the Zichron Moshe shul in Yerushalayim. They decided to travel towards Yericho, and hopefully spot the moon there. They figured that the eastern part of Israel was hotter, and maybe had less clouds. They were approaching Yericho, and were stopped at a checkpoint. The sky there was filled with clouds as well. They asked one of the soldiers if they could put out a message asking soldiers in other locations if anyone could see the moon from where they were stationed. The soldier was dumbfounded by the request, and asked the Rebbe why he wanted to know such information. The Rebbe told him about the mitzva of Birkat HaLevana, and how there were only a few hours left to do it. The soldier put out the request, and almost every reply was negative, except for one, who said he was near Me'arat HaMachpela, and he was able to see the moon. The Rebbes became so excited, and urged their driver to go there immediately. The soldier told them by the time they got there, the moon would probably be gone, but they didn't pay any attention to him, and they hurried there at once. When they finally arrived, it was two o'clock in the morning. Baruch Hashem, the moon was still visible, and they recited Birkat HaLevana with great jubilation. Even though it was very late, and they were extremely tired, they wanted to take advantage of the fact that they just did a mitzva with great self-sacrifice. One of the Rebbe's sons was with them, who was married for twenty years without children. They decided to go to Kever Rachel to pray, and there they prayed from the depths of their hearts, and miraculously, that year, the Rebbe's son was zocheh to have his first child. The value of a mitzva done with great difficulty is enormous. If we ever set out to do a mitzva and we run into obstacles, it's a gift from Hashem to enable us to get a much bigger mitzva for the very same deed, but it requires effort and perseverance. Hashem never wants to stop us from getting a mitzva. He only wants to make it better for us.