Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "Don't Stop Believing." The back contains a handwritten note featuring a quote from the Brazilian author Paulo Coelho, as well as the stock signature: "From your friends at West Allegheny Middle School."

Letter written on a torn piece of paper. The letter reads: "Olam Chesed Yibaneh (Your steadfast love is confirmed forever). We will build the world with love for you and for all. [Star of David] Shalom Blessings and Love."

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a bird with a leaf in its mouth and floral and geometric motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Folded card on blue paper with various taped cutouts. Front cover contains a white heart-shaped cutout. Inside features cutouts in the shape of a house, sun, and blue sky. The sun's rays are illustrated in colored pencil.

Letter from a member of the Point Loma Community Presbyterian Church in San Diego, California. The letter is dated 11/4/2018 and reads: "To the Tree of Life Synagogue, Our love and support go out to you. Only the Love of God in us can help to overcome such a tragedy and grief. Stay strong, stay united, and know that we at Point Loma Church in San Diego are praying for you and remembering you. With His Love, Geri [last name redacted]."

Post-it note with handwritten message in black ink. The message reads: "We stand with you!" Signed: "Douglas [last name redacted] and family."

Printed floral tags from floral arrangements sent by Shadyside Presbyterian Church.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of a bird with a leaf in its mouth and geometric and floral motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Post-it note with handwritten message in black and red marker. The message reads: "God bless all people of Pittsburgh. Our hearts are with you. [Heart]."

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside contains a quote from 1 Peter 4:3 about love and a prayer for God's love. The church's contact information is included on the back of the envelope.

Square card with white and yellow text against blue background. Card reads, "Mitzvah4Pittsburgh. Some spread darkness. We spread light. Choose a good deed. Choose a Mitzvah. Add light to the world," followed by four options and a place for respondents to list their name and email address. Some names and email addresses have been redacted for privacy.

Note from a member of The Church at Severn Run in Severn, Maryland. The note is enclosed in an envelope with church letterhead, reading: "The Church at Severn Run: Love Well, Live Jesus, Believe Big!" The note inside reads: "Dear friend, Greetings and peace be with you today. I thank God for the opportunity to write to you this morning. I just wanted to let you know that I am committed to praying for you and serving our communities together. The world is full of broken people. Some of these broken people have caused unimaginable pain. To you my Jewish friends.

Card from a student at West Allegheny Middle School in Imperial, Pa. The front features a hand-colored illustration of the words: "Keep Going" and arrows, stars, and other floral motifs. The back contains a handwritten note, as well as the stock signature: "From your friends at West Allegheny Middle School."

Folded card with marker illustration. Cover reads, "You are great the way you are and nothing can stop that no matter what." Interior reads, "I hope you guys feel better. This card is for you and I hope it makes you guys feel better. You guys should be treated the way you are no matter what. Don't let people hurt you. You are stronger than them" and the name "Howard [last name redacted for privacy]." Back cover reads "I wish you the best of luck" with smiling heart.

Card with colored pencil and marker illustration. When opened, front side shows illustrations of two five pointed stars and a stack of hearts, and is inscribed: "Margow. We are sorry for your loss." Back shows a tree with spiral-shaped branches and heart-shaped bow and arrows with a rectangular border with hearts in each corner.

Envelope and floral tag addressed to Jerry Rabinowitz. The envelope reads: "Jerry" and is illustrated with a heart and tree with barren branches. The tag features an illustration of a sheep with wildflowers growing out of its head. The tag contains a personal message to Jerry and features an illustration of a grass field with tree, large heart, and flowers in the lower center.

Hallmark card from a member of St. Peter's Episcopal Church in Londonderry, New Hampshire. The envelope contains a handwritten message: "With Peace and in Repentance and friendship of Spirit." The front cover reads: "Peace" and features a sandy landscape with a blue sky and orange flowers. The inside reads: "Dear Friends in the God of Abraham, My spirit and my prayers have been with you this past week. Prayers of love, courage, hope, and prayers of repentance for all little ways in which my own way of living accommodates any hatred, bigotry, or antisemitism.

Printed tag with Tree of Life synagogue emblem in the upper right. The tag reads: "America Stands with You." Creasing and staining due to exposure to the elements at the Wilkins memorial.