Следующий нижний индекс выполняет именно то, что вы просили:
Sub DoThaThing()
Dim i As Long, lastRow1 As Long
Dim Sheet1A As Variant, Sheet1F As Variant, firstFound As String
Dim findData As Range
lastRow1 = Sheets("Sheet1").Cells(Rows.Count, "A").End(xlUp).Row
For i = 1 To lastRow1 Step 1
Sheet1A = Sheets("Sheet1").Cells(i, "A").Value
Sheet1F = Sheets("Sheet1").Cells(i, "F").Value
Set findData = Sheets("Sheet2").Columns("A:A").Find(What:=Sheet1A, _
After:=Sheets("Sheet2").Range("A1"), _
LookIn:=xlValues, _
LookAt:=xlWhole, _
SearchOrder:=xlByColumns, _
SearchDirection:=xlNext, _
MatchCase:=False, _
SearchFormat:=False)
If Not findData Is Nothing Then
'First instance found, loop if needed
firstFound = findData.Address
Do
'Found, check Column F (5 columns over with offset)
If findData.Offset(0, 5).Value = Sheet1F Then
'A and F match get data from B (1 column over with offset)
Sheets("Sheet1").Cells(i, "B").Value = findData.Offset(0, 1).Value
Exit Do
Else
'F doesnt match, search next and recheck
Set findData = Sheets("Sheet2").Columns("A:A").FindNext(findData)
End If
Loop While Not findData Is Nothing And firstFound <> findData.Address
Else
'Value on Sheet 1 Column A was not found on Sheet 2 Column A
Sheets("Sheet1").Cells(i, "B").Value = "NOT FOUND"
End If
Next
End Sub
Редактировать: Исправлен бесконечный цикл.