In Acts 9:36, it is said to be a habit of Tabitha.
In Acts 10:38, it is said to be characteristic of Jesus.
Romans 2:7 calls it rewardable.
Galatians 6:9 encourages us not to get tired of it.
TItus 2:7 says it's a good way to set a good example; and 3:1 calls us to be ready about it. A few verses later in 3:8 and 14, we're admonished to be devoted to it.
I Peter 2:15 suggests that it might silence our accusers - but warns five verses later in 20 that it may cause us suffering anyway - and confirms in 3:17 that suffering for it still beats the alternative.
And James 4:17 agrees.
What is it?
Scan through the gospels. Flip through the Acts of the Apostles. See if it's not true that it was one of two primary foci of Jesus and His followers. One was good news. The other was doing good.
One let people know that God cares about them in the hereafter. The other let them know that He cares about them in the here-and-now.
The saints of scripture and their Savior didn't seem to spend a lot of time in meetings discussing the best way to achieve it, or what the most efficient use of resources might be to get it done, or whether it was scriptural to do good on certain days or in certain ways. They simply followed the gospel according to Nike:
Just do it.