What is the biblical definition of a blessing? What is it to bless in the Bible?

TL;DR:

The biblical definition of blessing includes praising or congratulating as well as a state of happiness. Blessing refers especially to people who live according to God’s ways, not for salvation but for the joy that comes as a result.

what does the bible say?

Blessing, as understood in both the Old and New Testaments, transcends mere good fortune, representing divine favor and alignment with God’s will. In Hebrew (barak), blessing involves praising God and being a channel of His favor, as seen in God’s covenant with Abram to bless him and make him a blessing to others (Genesis 12:1–3). This extends to happiness (esher) for those who obey God’s Word (Psalm 1:1; Proverbs 3:1–4). In the New Testament, blessings (eulogeo) are pronounced to reflect God’s grace, such as Jesus blessing children and food (Mark 10:16; Matthew 14:19). Blessing whether toward God or from God calls Christians to take to heart and live out God’s goodness, responding with kindness (1 Peter 3:9) and acknowledging our blessings in Christ (Ephesians 1:3). Ultimately, blessing finds fulfillment in Christ, in who He is and what He has done in saving us.

from the old testament

The word "bless" is used to translate the Hebrew word barak, which means "to praise, congratulate or salute." The Hebrew word barak means literally "to kneel" (Genesis 1:22; 12:2; Numbers 6:24–26; Psalm 103:1–2). In the common vernacular, blessing is used to indicate a wish of good fortune upon the one receiving the blessing.
In Genesis 12:2–3, God makes a promise to Abram, saying, "I will make of you a great nation, and I will bless you and make your name great, so that you will be a blessing. I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed." God promised good fortune and a good future to the descendants of Abram, and He said that others will also experience blessing through Abram.
Another word translated "blessing" is the Hebrew word esher, which indicates a state of happiness. This word occurs frequently in the Psalms and Proverbs. When the Psalmist says, "Blessed is the man who walks not in the counsel of the wicked, nor stands in the way of sinners, nor sits in the seat of scoffers" (Psalm 1:1), he is saying that walking in God’s ways gives us the best opportunity of happiness as opposed to walking in the counsel of the wicked or living as sinners do. Obedience to God does not save us nor guarantee us material prosperity or everything we want; rather, obedience to God and living according to His Word is a recipe for blessing, for happiness in life (Proverbs 3:1–4).

from the new testament

There are two Greek words in the New Testament translated as "blessing." The first is makarios, which carries the same meaning as the Hebrew word esher. The other is eulogeo, which is used to give a good report or say a good word; it is more similar to the meaning of barak.
We bless God for all the blessings He gives us in Christ (Ephesians 1:3). We are also to bless those who mistreat us, because we were called to receive a blessing from God (1 Peter 3:9). The relationship of believers to God, our submission to Him and His gifts toward us, are described in terms of blessing, and indeed, there is no blessing as meaningful or as permanent as our inheritance in Christ (Galatians 3:18; 1 Peter 1:4).
Jesus blesses (eulogeo) the children (Mark 10:16).
Jesus blesses the five loaves and two fish before feeding the multitude (Matthew 14:19).
God calls us to pronounce blessing (eulogeo) on those who curse us and to not repay evil for evil but to repay with blessing (1 Peter 3:9).
God tells us that we have been blessed (eulogeo) in Christ and therefore bless (eulogeo) God (Ephesians 1:3).
James 3:9 warns us about the dangers of not having self-control with our words. He tells us that with our mouth we pronounce cursing and blessing (eulogeo) and that it should not be so.
In Revelation 5:13, every creature in heaven proclaims blessing (eulogeo) upon Jesus: “To him who sits on the throne and to the Lamb be blessing and honor and glory and might forever and ever!”
The Beatitudes tell us that those who live out God’s kingdom values will be blessed (makarios), will experience God’s happiness (Matthew 5:2–12; Luke 6:20–23).

implications for today

Blessing extends beyond mere good fortune or happiness; it reflects a deep alignment with God’s will and character. In the Old Testament, the Hebrew concept of "blessing" (barak) involves not only receiving favor from God but also becoming a channel through which others are blessed. In Genesis 12, God expresses this as He promises Abraham that He will bless the whole through him. Believers are called to live this out. The happiness we have in Him is to come out in the way we treat others. As we embody God’s goodness and grace in our interactions we can, for example, respond to mistreatment with kindness and acknowledging God’s abundant blessings in our lives. We can do good to others, especially the household of God (Galatians 6:10). Ultimately, true blessing is found in our relationship with Christ, experiencing God’s redemption and transformation in our lives and sharing God’s enduring love and favor with the world.

understand

God promised Abram blessings to make him a blessing to the entire world, emphasizing a covenantal relationship and God’s redemptive plan.
There are two words in Hebrew for blessing: barak and esher. "Barak," signifies praising God, expressing reverence, and bestowing favor. "Esher," meaning blessed or happy, is linked to obeying God’s Word and living righteously.
Makarios and eulogeo are the Greek words for blessing.

reflect

How does understanding the biblical definition of blessing reshape your perspective on what it means to be blessed in your life?
How can you actively become a channel of God’s blessing to others?
How have you experienced God’s blessings—both in moments of joy and challenges—and how has this shaped your faith?

engage

The word "bless" or "blessing" comes from the Old English word bledsian, based on the Old English word for blood. It may have originally meant "to consecrate with blood" and it was later used to translate the Latin word benedicere, which means "to praise, worship."
How does the Old Testament concept of blessing (barak and esher) inform our understanding of God’s covenantal relationship with His people? How does this relate to our role in sharing God’s blessings with others?
Discuss the significance of Jesus’ actions in the New Testament—such as blessing the children and the food—using the Greek words makarios and eulogeo. How do these instances illustrate God’s character of blessing and our call to bless others?