But if you do not forgive, your Father also, who is in heaven, will not forgive your trespasses.”
This word is a very serious warning. An unforgiving heart is contrary to the spirit of the Gospel. A person who wants to receive forgiveness from God but refuses to forgive others, by his conduct denies the grace on which he is hoping. The Lord here does not teach that God’s forgiveness is bought by our forgiving, but shows that a person who has truly received God’s grace cannot remain continually merciless and hard-hearted. Forgiveness is one of the necessary fruits of a saved heart. If that fruit is persistently and knowingly absent, it testifies that the person has not yet humbled himself before God’s mercy.