Let’s answer your second question first, “Can persons with disabilities or with mental illnesses by saved?” We need to ask first, “How is a person saved?’ A person is saved by repenting of their sins and believing on the Lord Jesus Christ. The penitent jailor in Acts chapter came “trembling before Paul and Silas…and said, ‘Sirs, what must I do to be saved?’” (Verses 29-30…NKJV). He obviously had a “change of mind” (which is what the word “repent” means) about his sinful and lost condition before God and he desired to be saved from the penalty of his sin. He had no doubt heard them singing about God’s salvation through Christ (see verse 25) and now he wanted to experience God’s salvation for himself. Paul and Silas told him, “Believe on the Lord Jesus Christ, and you WILL BE SAVED” (verse 31). We know, from the verses that follow, that he did put his faith in Christ as the One who “came to seek and TO SAVE THAT WHICH IS LOST” (Luke 19:10). He believed that Jesus, the Son of God, became a Man in order to take the lost sinner’s place in death and judgment on the cross of Calvary (see Hebrews 2:9; 1st Peter 2:24; 3:18; and 2nd Corinthians 5:21).

Can a disabled person repent of their sins and believe on the Lord Jesus Christ? If we are talking about a “physical disability” the answer is a definite YES. They need only to have the ability to see that: 1) they are a lost sinner before a holy God (Luke 18:13); 2) they deserve death and judgment because of their sin (Romans 6:23 and Hebrews 9:27); and 3) Christ “came into the world to save sinners” (1st Timothy 1:15) and on the cross He “put away sin by the sacrifice of Himself” (Hebrews 9:26).

Can a person with a mental illness repent of their sins and believe on the Lord Jesus Christ? It depends on the nature of the mental illness. Some people are born with a serious mental handicap like “down syndrome” which leaves them unable to grasp the concept of sin, God, and the need for salvation. They are like “little children” who are not of the age of accountability. We read of these in Matthew chapter 18 where Jesus spoke about “little children” who die and are in heaven. In verses 10-11 Jesus said, “Take heed that you do not despise ONE OF THESE LITTLE ONES, for I say that IN HEAVEN their angels always see the face of My Father who is in heaven. For the Son of the Man has COME TO SAVE THAT WHICH WAS LOST.” It is clear from these verses that little ones who die before they reach the age of accountability are in heaven beholding the face the God the Father and they are there because Jesus came to save them. They were born lost sinners but Jesus “came to save that which was lost.” We saw earlier in Luke 19:10 that Jesus “came TO SEEK and TO SAVE that which is lost,” for in that passage He was speaking of those who are able to understand they are sinners in need of a salvation, so He has to SEEK THEM before He can SAVE THEM. But with “little children” and those who are “like little children due to a mental handicap,” He doesn’t seek them but He still had to die for them to SAVE THEM. Now there may be those who were not born with a mental illness who later in life develop a mental illness like dementia or Alzheimer’s disease. In their case their eternal destiny (salvation) will be determined by how they responded to God’s offer of salvation through Jesus Christ BEFORE they became mentally ill.

As to your question, “Can persons with disabilities or mental illnesses be spiritually involved,” the answer is, “Yes, if they have trusted in the Lord Jesus Christ for their salvation.” A physical disability will not prevent a true believer from growing spiritually and serving the Lord. I held Bible studies in a “High rise for handicapped people” for nearly 30 years and many believers came to the Bible studies with a real love for their Savior and a real hunger for the Word of God. They were also known for witnessing to their unsaved neighbors and for asking other residents to come to the Bible studies. I was so encouraged to see their zeal for the Lord and even though most of them were in wheelchairs their minds and hearts were not disabled and thus they served their Lord and Savior admirably. Some believers that came out had a mental disability but it was not severe enough to prevent them from growing spiritually and serving the Lord. It took some of them longer to comprehend various scriptures and to articulate what they were learning, but they were still, in measure, “spiritually involved.”  (476.5)  (DO)