In Numbers 14:20-35 God responds to Moses' plea to forgive the Israelites for their persistent grumbling, complaining and disobedience. What is God's response? Notice that God forgives the grumbling Israelites for their sin. He does so by not cutting them off from His presence and destroying them completely. They are still His people. However, He refuses to allow those Israelites to enter the Promised Land. He says, "I have forgiven them, as you asked. Nevertheless...not one of them will enter the land I promised on oath to their ancestors. No one who has treated me with contempt will ever see it." (v20-23)
What does that tell us? God is ready, willing and able to forgive our sins (1 John 1:9). However, just because God forgives us does not mean that we will still receive all the same blessings and opportunities that God would have given us if we hadn't sinned. For example, if a man cheats on his wife and later sincerely repents to God, God in His mercy will forgive that man, but there are still real consequences arising from his adultery that he, his wife and his family will need to deal with. Despite God's forgiveness, there are still real consequences for our sin.
Thus it is foolish for a person to think, "I'll go ahead and sin, since God will forgive me anyways." It's true that God will forgive you if you sincerely repent, but like the Israelites in Numbers 14, if you choose to sin there's a real risk that you will lose some huge blessings and opportunities that God would have given you if you had remained faithful. That's why holiness and doing our best to obey God are still so important; they still impact the amount of blessing that will flow in and through our lives.
Forgiveness and trust are not the same thing. Notice that God forgave those Israelites who sinned against Him, but He did not trust them in the same way as before. In a similar way, God's Word commands us to forgive those who sin against us. But we are not commanded to trust them again. Forgiving someone and trusting them again are two different things.
Forgiveness means that you let go of the debt, the anger and the resentment you held against the person who hurt you. But forgiveness does not mean you need to trust that person again and go back to the way things used to be. In some cases, to trust that person again, especially when that person has not sufficiently changed, would be stupid. In not all but some cases, you might need to make that distinction between forgiving that person and trusting them again.
Remember: Forgiveness is free, but trust is earned.
May we be a people who not only receive God's forgiveness, but also a people who can be trusted with God's blessing.