“Grace” by another word is “Favor”. It comes from the Greek word “charis” where English also gets the words “Mercy” and “Charity”. Grace or Favor is doing something for someone they could not do for themselves, like a helping hand up.
Imagine there’s a God who is holy, perfect, sinless, and loving in every way. He’s all knowing, all powerful and everywhere all the time. Imagine God knows you’re sinful, imperfect and unholy. In fact your sinful, imperfect unholy existence offends his holy, perfectly, sinless nature. But God loves you so much, he’d rather die for you once in humanity, to atone for your sinful, imperfect nature, than to live forever without you, for all of eternity. So, he incarnates himself in Jesus Christ to die in perfect sinless, humanity, on a cross on a hill called Calvary, just outside of Jerusalem because God loves you so very, very much.
To make sure you, and others, know about his unconditional love and amazingly gracious offer, God sends his Holy Spirit into the world throughout all generations and centuries, to call and invite you, and others, to accept and receive his gracious offer of atonement for your imperfect human sinful nature. Doing for you what you could never do for yourself, by changing you, causing you to be “Born Again” by God’s Holy Spirit, becoming like Jesus’ nature, not sinless, or perfect on Earth, like Jesus is, but to be holy and “blameless” for your sinful imperfection, sealing you for salvation from a horrible place called Hell, to a wonderful eternal paradise with God called Heaven. Thus changing your life and destiny forever for all of eternity.
All you have to do is respond to and receive God’s unconditional love, helping hand and amazing grace by genuinely, sincerely, believe in your heart and confess with your mouth and prove by your lifestyle, that Jesus is Lord of all and of your life, willing to be changed by his Holy Spirit. That's what faith in “the God of all Grace who called you to his eternal glory in Christ Jesus, shall restore you and make you firm, steadfast and strong” (1Peter5:10) is.
All of this is based on The Bible, Old and New Testaments, which have been proven true in over 101 ways in the areas of science, nature, archeology, and history. If the Bible is proven true about so many things we already know about, logic says, it’s probably true about things we have not yet seen, like eternal existence in either Heaven for those who receive God’s gracious helping hand, or in Hell for those who refuse and reject it. If the Bible is wrong, you’ve lost nothing. But if it's right, and you reject it, you’ve lost everything. Everyone is born to live forever in one of two places. People either live by God’s grace or by their guilt. No one gets to Heaven by themself.
In addition to salvation the God of all grace does favors for people everyday. James 1:17 says, "Every good and perfect gift comes down from the heavenly Father of lights (or father of heavenly lights depending on the version)." Gifts are grace, favors, you ca't and don't earn or deserve. You just receive them from God. Look at all the good stuff you have in your life. Where do you think all the good stuff comes from; the unexpected open doors of opportunities, yours husband, wife, parents, children, friends, family and material good things, from the clothes you wear, to the house your live in, to the food you eat. Where do you think all that good stuff comes from? It comes from God doing favors for you, showering you with his grace. The next time your faith is tested and you're up against it, backed into a corner, up against a wall, needing a helping hand, don't panic, remember to ask the God of all grace to help you. And you'll see that he does.