According to Matthew 5:4, those who mourn will be comforted. What does this mean? Those who mourn refers to individuals who mourn over personal sin, over general ungodliness, and because God is being dishonored. Our personal sin bothers us enough to lead us to repentance rather than to a mere sorrow for possible negative consequences (2 Corinthians 7:10). We accept that, in our own strength, we are helpless to escape the power of sin in our lives (Romans 7:24). Hence, we are distressed and cry out to the Lord because, also being poor in spirit, we look to Him. We rely on the Lord. Naturally, this will produce in us greater compassion for those who are also distressed.
Such individuals will be comforted. How? Sometimes, comfort comes from the Lord removing the affliction (Acts 12:5-7). In other instances, He allows the affliction to continue but comforts us by bringing about immediate (Romans 8:28) and long-term good (2 Corinthians 4:17). This comfort is partial now during this present evil age (Isaiah 61:3) but will be fully realized later (Revelation 7:17). Of course, the greatest comfort is being forgiven and put in right relationship with the Lord (apart from which all other comfort is ultimately pointless). All the blessings of the poor in spirit, who are the same individuals as those who mourn, can also be means of comfort. Let us bring glory to Him by mourning and being comforted.
Instead of being timid, learn to be appropriately bold.