Please, I would like to ask the following questions:
Is it scriptural for the church to organize a send-forth program for its outgoing preacher, elder, or faithful member who is relocating? The program typically involves citation, extolling of virtues, prayers, and presentation of gifts purchased by both the church and individual brethren.
Is it biblical for youths in a congregation to raise funds to buy gifts for a fellow youth who will be getting married? Also, how about sisters doing the same?
Thanks in anticipation of your scriptural answers.
The work of the church can be categorized into three areas: teaching the world, teaching its members, and care for needy Christians. See The Work of the Church for details. Holding parties for departing members doesn't fit in any of these categories; thus, the burden is to show that God commanded the church to do some area of work that would include holding parties for members. I don't know of any.
This is not to say it is wrong to show appreciation for members who are leaving. "But we request of you, brethren, that you appreciate those who diligently labor among you, and have charge over you in the Lord and give you instruction, and that you esteem them very highly in love because of their work. Live in peace with one another" (I Thessalonians 5:12-13). However, this is something members should do all the time, not just when someone is leaving. And this what the brethren are to do, not the church. See Individual Duty or Local Church Duty?
The church's funds exist to finance the church's work on behalf of God. The funds should be views as belong to God and not men. Thus, it is God who declares what the church is to do and how to spend its funds. Presents to members is not an authorized church work. It falls to the Christians to do nice things for each other. If Christians want to raise money to give a gift, that is their decision and must not involve the church.