The angel of the Lord would go before them to prepare the way, and they were to obey Him. There are parallels here between the angel of the Lord and the Holy Spirit, maybe even between the instruction that they would not be forgiven if they did not obey the angel, and the warning about blaspheming the Holy Spirit.
The role of the angel was to lead them safely to the destination, so it is with the Holy Spirit. The Spirit bears witness to Christ and teaches us the ways of God. If we follow Him then we will find that God will defeat all obstacles in the way. Now we need to note that the role of the Spirit is to lead us to God's destination following God's chosen path for our life in God's chosen way. He is not there to do our bidding!
There are severe warnings about not adopting the ways of the nations. We too need to be careful about this. This is not to say that all the ways of the world are wrong, sometimes they do do things in a righteous manner, but we must not worship false idols.
There were many obstacles in the way, other nations that were inhabiting the Promised Land. So we too face many obstacles, but God will remove the obstacles "little by little". He does this step by step as we grow in character, so that we can safely occupy the land.